Endocyte (ECYT) 10-K 5 Mar 14 2013 FY Annual report Financial data

Document_And_Entity_Informatio

Document And Entity Information (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2013	Feb. 24, 2014	Jun. 28, 2013
Document Information [Line Items]	'	'	'
Entity Registrant Name	'ENDOCYTE INC	'	'
Entity Central Index Key	'0001235007	'	'
Current Fiscal Year End Date	'--12-31	'	'
Entity Filer Category	'Accelerated Filer	'	'
Trading Symbol	'ECYT	'	'
Entity Common Stock, Shares Outstanding	'	36,180,617	'
Document Type	'10-K	'	'
Amendment Flag	'false	'	'
Document Period End Date	31-Dec-13	'	'
Document Fiscal Period Focus	'FY	'	'
Document Fiscal Year Focus	'2013	'	'
Entity Well-known Seasoned Issuer	'No	'	'
Entity Voluntary Filers	'No	'	'
Entity Current Reporting Status	'Yes	'	'
Entity Public Float	'	'	$406.70

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	Dec. 31, 2013	Dec. 31, 2012
Current assets:	'	'
Cash and cash equivalents	$52,846,940	$33,996,866
Short-term investments	70,434,148	141,840,823
Receivables	6,353,180	5,689,067
Prepaid expenses	3,200,924	2,799,883
Other assets	496,338	498,203
Total current assets	133,331,530	184,824,842
Long-term investments	25,571,659	25,540,649
Property and equipment, net	3,839,426	3,166,905
Other noncurrent assets	114,961	546,313
Total assets	162,857,576	214,078,709
Current liabilities:	'	'
Accounts payable	5,435,473	3,647,967
Accrued wages and benefits	3,065,905	2,426,534
Accrued clinical trial expenses	3,728,015	2,486,967
Accrued interest payable	'	0
Accrued expenses	1,668,944	1,902,910
Deferred revenue	59,746,952	51,993,200
Current portion of other liabilities	18,168	12,647
Total current liabilities	73,663,457	62,470,225
Other liabilities, net of current portion	33,458	42,065
Deferred revenue, net of current portion	931,940	51,993,141
Total liabilities	74,628,855	114,505,431
Stockholders’ equity:	'	'
Common stock: $0.001 par value, 100,000,000 shares authorized; 35,919,019 and 36,155,509 shares issued and outstanding at December 31, 2012 and 2013	36,156	35,919
Additional paid-in capital	262,060,590	255,356,888
Accumulated other comprehensive income	56,691	72,749
Retained deficit	-173,924,716	-155,892,278
Total stockholders’ equity	88,228,721	99,573,278
Total liabilities and stockholders’ equity	$162,857,576	$214,078,709

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Common stock, par value (in dollars per share)	$0.00	$0.00
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	36,155,509	35,919,019
Common stock, shares outstanding	36,155,509	35,919,019

CONSOLIDATED_STATEMENTS_OF_OPE

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenue:	'	'	'
Collaboration revenue	$64,870,919	$34,682,111	$191,023
Total revenue	64,870,919	34,682,111	191,023
Operating expenses:	'	'	'
Research and development	57,898,971	35,670,418	28,827,746
General and administrative	25,313,731	15,054,369	10,000,000
Total operating expenses	83,212,702	50,724,787	38,827,746
Loss from operations	-18,341,783	-16,042,676	-38,636,723
Other income (expense), net:	'	'	'
Interest income	465,505	327,745	129,449
Interest expense	-2,458	-628,993	-1,987,873
Other income (expense), net	-153,702	-947,834	-36,466
Net loss	-18,032,438	-17,291,758	-40,531,613
Net loss per share - basic and diluted (in dollars per share)	($0.50)	($0.48)	($1.40)
Items included in other comprehensive income (loss):	'	'	'
Unrealized gain (loss) on foreign currency translation	-6,805	707	-5,718
Unrealized gain (loss) on available-for-sale securities	-9,253	78,306	-546
Other comprehensive income (loss)	-16,058	79,013	-6,264
Comprehensive loss	($18,048,496)	($17,212,745)	($40,537,877)
Weighted-average number of common shares used in net loss per share calculation - basic and diluted (in shares)	36,036,996	35,858,757	29,003,991

CONSOLIDATED_STATEMENTS_OF_CON

CONSOLIDATED STATEMENTS OF CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) (USD $)	Total	Convertible Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]
Balances at the beginning at Dec. 31, 2010	($96,911,023)	$89,799,483	$1,203	$1,156,681	$0	($98,068,907)
Balances at the beginning (in shares) at Dec. 31, 2010	'	11,747,563	1,203,228	'	'	'
Fair value adjustment of the subordinated notes	-644,118	0	0	-644,118	0	0
Net proceeds from public offerings	144,902,733	0	20,215	144,882,518	0	0
Net proceeds from public offerings (in shares)	'	0	20,214,810	'	'	'
Conversion of preferred stock to common stock	89,799,483	-89,799,483	11,747	89,787,736	0	0
Conversion of preferred stock to common stock (in shares)	'	-11,747,563	11,747,563	'	'	'
Reclassify warrants to equity	223,031	0	0	223,031	0	0
Conversion of subordinated notes to common stock	13,983,777	0	2,336	13,981,441	0	0
Conversion of subordinated notes to common stock (in shares)	'	0	2,335,823	'	'	'
Exercise of stock options	595,572	0	284	595,288	0	0
Exercise of stock options (in shares)	283,061	0	283,061	'	'	'
Stock-based compensation	1,960,345	0	0	1,960,345	0	0
Net loss	-40,531,613	0	0	0	0	-40,531,613
Unrealized gain (loss) on foreign exchange translation	-5,718	0	0	0	-5,718	0
Unrealized gain (loss) on securities	-546	0	0	0	-546	0
Balances at the ending at Dec. 31, 2011	113,371,923	0	35,785	251,942,922	-6,264	-138,600,520
Balances at the ending (in shares) at Dec. 31, 2011	'	0	35,784,485	'	'	'
Exercise of stock options	391,407	0	134	391,273	0	0
Exercise of stock options (in shares)	134,534	0	134,534	'	'	'
Stock-based compensation	3,022,693	0	0	3,022,693	0	0
Net loss	-17,291,758	0	0	0	0	-17,291,758
Unrealized gain (loss) on foreign exchange translation	707	0	0	0	707	0
Unrealized gain (loss) on securities	78,306	0	0	0	78,306	0
Balances at the ending at Dec. 31, 2012	99,573,278	0	35,919	255,356,888	72,749	-155,892,278
Balances at the ending (in shares) at Dec. 31, 2012	'	0	35,919,019	'	'	'
Exercise of stock options	644,934	0	189	644,745	0	0
Exercise of stock options (in shares)	188,699	0	188,699	'	'	'
Exercise of warrants	0	0	48	-48	0	0
Exercise of warrants (in shares)	'	'	47,791	'	'	'
Stock-based compensation	6,059,005	0	0	6,059,005	0	0
Net loss	-18,032,438	0	0	0	0	-18,032,438
Unrealized gain (loss) on foreign exchange translation	-6,805	0	0	0	-6,805	0
Unrealized gain (loss) on securities	-9,253	0	0	0	-9,253	0
Balances at the ending at Dec. 31, 2013	$88,228,721	$0	$36,156	$262,060,590	$56,691	($173,924,716)
Balances at the ending (in shares) at Dec. 31, 2013	'	0	36,155,509	'	'	'

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating activities	'	'	'
Net loss	($18,032,438)	($17,291,758)	($40,531,613)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:	'	'	'
Depreciation	674,725	358,367	262,518
Stock-based compensation	6,059,005	3,022,693	1,960,345
Loss on disposal of property and equipment	1,778	6,354	20,876
Loss on extinguishment of debt	0	992,281	0
Accretion of bond premium	1,246,143	961,271	343,342
Non cash interest expense	0	73,914	646,069
Change in operating assets and liabilities:	'	'	'
Receivables	-2,508,687	-1,409,738	0
Prepaid expenses and other assets	2,016,928	-1,287,834	932,333
Accounts payable	-386,241	524,936	943,024
Accrued interest, wages, benefits and other liabilities	1,337,021	3,483,896	838,490
Deferred revenue	-41,488,719	99,757,129	0
Net cash provided by (used in) operating activities	-51,080,485	89,191,511	-34,584,616
Investing activities	'	'	'
Purchases of property and equipment	-827,839	-1,862,872	-234,969
Purchases of investments	-125,026,602	-265,203,590	-236,930,028
Proceeds from sale of investments	195,146,871	163,671,395	169,853,899
Net cash provided by (used in) investing activities	69,292,430	-103,395,067	-67,311,098
Financing activities	'	'	'
Proceeds from issuance of subordinated convertible notes, net of issuance costs	0	0	3,590,837
Principal payments on borrowings	0	-13,544,175	-2,708,011
Proceeds from initial public offering, net of issuance costs	0	0	78,167,843
Proceeds from second public offering, net of issuance costs	0	0	66,734,890
Proceeds from the exercise of stock options	644,934	391,407	595,573
Net cash provided by (used in) financing activities	644,934	-13,152,768	146,381,132
Effect of exchange rate	-6,805	707	-5,718
Net increase (decrease) in cash and cash equivalents	18,850,074	-27,355,617	44,479,700
Cash and cash equivalents at beginning of period	33,996,866	61,352,483	16,872,783
Cash and cash equivalents at end of period	$52,846,940	$33,996,866	$61,352,483

Nature_of_Business_and_Organiz

Nature of Business and Organization	12 Months Ended
	Dec. 31, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	'
	1. Nature of Business and Organization
	Endocyte, Inc. (the “Company”) is a biopharmaceutical company developing targeted therapies for the treatment of cancer and inflammatory diseases. The Company uses its proprietary technology to create novel small molecule drug conjugates (“SMDCs”), and companion imaging agents. The SMDCs actively target receptors that are over-expressed on diseased cells, relative to healthy cells. This targeted approach is designed to enable the treatment of patients with a highly active drug at greater doses, delivered more frequently, and over longer periods of time than would be possible with the untargeted drug alone. The Company is also developing companion imaging agents for each of its SMDCs that are designed to identify the patients whose disease over-expresses the target of the therapy and who are therefore more likely to benefit from treatment.
	The Company has two wholly-owned subsidiaries, Endocyte Europe B.V. and Endocyte Europe G.m.b.H, which have been formed to assist with the administration of the pending applications with the European Medicines Agency (“EMA”) and pre-commercial planning activities in Europe.
	Public Offerings
	On February 9, 2011, the Company completed its initial public offering of 14,375,000 shares of common stock, including 1,875,000 shares of common stock pursuant to the exercise of the over-allotment option by the underwriters. Proceeds, net of underwriting discounts, commissions and other transaction costs were approximately $78.2 million. Upon the closing of the offering, the outstanding Subordinated Convertible Promissory Notes (the “Subordinated Notes”) previously issued by the Company (see footnote 10) automatically converted into 2,335,823 shares of common stock using a conversion price of $5.10 per share (85% of the original issue price of the shares sold in the initial public offering), all of the outstanding shares of preferred stock were converted to common stock and the outstanding warrants to purchase Series C-3 preferred stock were converted to warrants to purchase common stock and reclassified from a liability to equity.
	On August 2, 2011, the Company completed a public offering of 4,968,321 shares of common stock, including 871,489 shares of common stock pursuant to the exercise of the over-allotment by the underwriters. Proceeds, net of underwriting discounts, commissions and other transaction costs were approximately $66.7 million.

Significant_Accounting_Policie

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Significant Accounting Policies [Text Block]	'
	2. Significant Accounting Policies
	Stock Split
	On January 10, 2011, the Company effected a 1.00 for 1.91 reverse stock split. All historical common stock and per share information has been changed to reflect the stock split.
	Basis of Presentation
	The accompanying consolidated financial statements include the accounts of Endocyte, Inc. and its subsidiaries and all intercompany amounts have been eliminated. The consolidated financial statements are prepared in conformity with U.S. generally accepted accounting principles (“GAAP”). Subsequent events have been evaluated through the date of issuance, which is the same as the date this Form 10-K is filed with the Securities and Exchange Commission.
	Use of Estimates
	The preparation of financial statements in conformity with GAAP requires the Company’s management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual amounts may differ from those estimates.
	Cash and Cash Equivalents
	The Company considers cash and all highly liquid investments with an original maturity of three months or less at the date of purchase to be cash equivalents. Cash equivalents consist primarily of money market instruments that are maintained by an investment manager.
	Investments
	Investments consist primarily of investments in U.S. Treasuries, U.S. Government agency obligations and corporate debt securities, which could also include commercial paper, that are maintained by an investment manager. Management determines the appropriate classification of marketable securities at the time of purchase and reevaluates such classification as of each balance sheet date. Available-for-sale securities are carried at fair value, with the unrealized gains and losses reported in other comprehensive income. Realized gains and losses and declines in value judged to be other-than-temporary on available-for-sale securities are included in other income. The Company considers and accounts for other-than-temporary impairments according to the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 320, Investments — Debt and Equity Securities (“ASC 320”). The cost of securities sold is based on the specific-identification method. Discounts and premiums on debt securities are amortized to interest income and expense over the term of the security.
	Property and Equipment
	Property and equipment are stated at cost and are being depreciated using the straight-line method over estimated useful lives, which range from three to seven years.
	Licenses and Patents
	Licenses and patent costs are expensed as incurred as the Company does not believe there is an alternate future use for the costs. Licenses are classified as research and development and patents are classified as general and administrative expenses in the consolidated statements of operations.
	Long-Lived Assets
	The Company reviews long-lived assets, including property and equipment, for impairment when events or changes in business conditions indicate that their full carrying value may not be fully recoverable.
	Leases
	The Company evaluates all leases to determine whether they should be accounted for as operating or capital leases.
	Revenue Recognition
	The Company recognizes revenues from license and collaboration agreements when persuasive evidence of an arrangement exists, delivery has occurred or services have been rendered, the fee is fixed or determinable, and there is reasonable assurance that the related amounts are collectible in accordance with ASC Topic 605, Revenue Recognition (“ASC 605”). The Company’s license and collaboration agreements may contain multiple elements, including grants of licenses to intellectual property rights, agreement to provide research and development services and other deliverables. The deliverables under such arrangements are evaluated under ASC Subtopic 605-25, Multiple-Element Arrangements. Effective January 1, 2011, the Company adopted an accounting standard update that amended the guidance on accounting for arrangements with multiple deliverables. Pursuant to the new standard, each required deliverable is evaluated to determine whether it qualifies as a separate unit of accounting based on whether the deliverable has “stand-alone value” to the customer. The arrangement’s consideration that is fixed or determinable, excluding contingent milestone payments, is then allocated to each separate unit of accounting based on the relative selling price of each deliverable. In general, the consideration allocated to each unit of accounting is recognized as the related goods or services are delivered, limited to the consideration that is not contingent upon future deliverables.
	Upfront payments for licensing the Company's intellectual property are evaluated to determine if the licensee can obtain stand-alone value from the license separate from the value of the research and development services and other deliverables in the arrangement to be provided by the Company. If the Company determines that the license does not have stand-alone value separate from the research and development services or other deliverables, the license, services and other deliverables are combined as one unit of account and upfront payments are recorded as deferred revenue in the balance sheet and are recognized in a manner consistent with the final deliverable. When stand-alone value is identified, the related consideration is recorded as revenue in the period in which the license or other intellectual property rights are delivered.
	In those circumstances where research and development services or other deliverables are combined with the license, and multiple services are being performed such that a common output measure to determine a pattern of performance cannot be discerned, the Company recognizes amounts received on a straight line basis over the performance period. Such amounts are recorded as collaboration revenue. Any subsequent reimbursement payments, which are contingent upon the Company’s future research and development expenditures, will be recorded as collaboration revenue and will be recognized on a straight-line basis over the performance period using the cumulative catch up method. The costs associated with these activities are reflected as a component of research and development expense in the statements of operations in the period incurred.
	Milestone payments under collaborative arrangements are triggered either by the results of the Company’s research and development efforts, achievement of regulatory goals or by specified sales results by a third-party collaborator. Milestones related to the Company’s development-based activities may include initiation of various phases of clinical trials and applications and acceptance for product approvals by regulatory agencies. Due to the uncertainty involved in meeting these development-based milestones, the determination is made at the inception of the collaboration agreement whether the development-based milestones are considered to be substantive (i.e. not just achieved through passage of time). In addition, the amounts of the payments assigned thereto are considered to be commensurate with the enhancement of the value of the delivered intellectual property as a result of the Company’s performance. Because the Company’s involvement is necessary to the achievement of development-based milestones, the Company would account for development-based milestones as revenue upon achievement of the substantive milestone events. Milestones related to sales-based activities may be triggered upon events such as first commercial sale of a product or when sales first achieve a defined level. Since these sales-based milestones would be achieved after the completion of the Company’s development activities, the Company would account for the sales-based milestones in the same manner as royalties, with revenue recognized upon achievement of the milestone.
	Royalties based on reported sales of licensed products will be recognized based on contract terms when reported sales are reliably measurable and collectability is reasonably assured. To date, none of the Company's products have been approved and therefore the Company has not earned any royalty revenue from product sales. In territories where the Company and the collaborator will share profit, the revenue will be recorded in the period earned.
	Research and Development Expenses
	Research and development expenses represent costs associated with the ongoing development of SMDCs and companion imaging agents and include salaries, supplies, and expenses for clinical trials. The Company records accruals for clinical trial expenses based on the estimated amount of work completed. The Company monitors patient enrollment levels and related activities to the extent possible through internal reviews, correspondence, and discussions with research organizations.
	Upfront payments made in connection with business collaborations and research and development arrangements are evaluated under ASC Subtopic 730-20, Research and Development Arrangements. Upfront payments made in connection with business development collaborations are expensed as research and development costs, as the assets acquired do not have alternative future use. Amounts related to future research and development are capitalized as prepaid research and development and are expensed over the service period based upon the level of services provided. As of December 31, 2013, the Company had approximately $2.3 million of capitalized research and development costs included in prepaid expenses and other noncurrent assets.
	Stock-Based Compensation
	The Company accounts for its stock options pursuant to ASC Topic 718, Compensation — Stock Compensation (“ASC 718”), which requires the recognition of the fair value, or calculated value for nonpublic entities, of stock-based compensation in net income. Stock-based compensation consists of stock options, which are granted at exercise prices at or above the fair market value of the Company’s common stock on the dates of grant. The Company has issued performance based restricted stock units (“PRSUs”) for which stock-based compensation expense will be recognized when the Company determines that it is probable that the performance conditions will be achieved. The Company used the calculated value method to measure its stock-based compensation prior to its initial public offering. The Company recognizes compensation cost based on the grant-date value estimated in accordance with the provisions of ASC 718.
	Net Loss Per Share
	The Company calculates basic net loss per share based on the weighted-average number of outstanding common shares. The Company calculates diluted net loss per share based on the weighted-average number of outstanding common shares plus the effect of dilutive securities.
	Income Taxes
	The Company accounts for income taxes under the liability method in accordance with the provision of ASC Topic 740, Income Taxes (“ASC 740”). ASC 740 requires recognition of deferred taxes to provide for temporary differences between financial reporting and tax basis of assets and liabilities. Deferred taxes are measured using enacted tax rates expected to be in effect in a year in which the basis difference is expected to reverse. The Company continues to record a valuation allowance for the full amount of deferred tax assets, which would otherwise be recorded for tax benefits relating to operating loss and tax credit carryforwards, as realization of such deferred tax assets cannot be determined to be more likely than not.
	The Company accounts for uncertain income tax positions recognized in the financial statements in accordance with Accounting Standards Update (“ASU”) No. 2009-06. This guidance prescribes a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return and provides guidance on derecognition of tax benefits, classification on the balance sheet, interest and penalties, accounting in interim periods, disclosure, and transition.
	Segment Information
	Operating segments are defined as components of an enterprise engaging in business activities for which discrete financial information is available and regularly reviewed by the chief operating decision maker in deciding how to allocate resources and in assessing performance. The Company is performing clinical trials globally and has established a subsidiary in The Netherlands to assist in the administration of filing applications with the EMA and a subsidiary in Switzerland for pre-commercial planning activities in Europe. All long-lived assets are held in the U.S. The Company views its operations and manages its business in one operating segment.

New_Accounting_Pronouncements

New Accounting Pronouncements	12 Months Ended
	Dec. 31, 2013
Accounting Changes and Error Corrections [Abstract]	'
Accounting Changes and Error Corrections [Text Block]	'
	3. New Accounting Pronouncements
	Recently Adopted Accounting Standards
	In January 2013, the FASB issued ASU No. 2013-01, Clarifying the Scope of Disclosures about Offsetting Assets and Liabilities, an update to ASC Topic 210, Balance Sheet. This update clarifies that the scope of Update 2011-11, Disclosures about Offsetting Assets and Liabilities, applies to derivatives accounted for in accordance with ASC Topic 815, Derivatives and Hedging, including bifurcated embedded derivatives, repurchase agreements and reverse repurchase agreements, and securities borrowing and securities lending transactions that are either offset in accordance with ASC Section 210-20-45 or ASC Section 815-10-45 or subject to an enforceable master netting arrangement or similar agreement. This update became effective for the Company for the fiscal year beginning on January 1, 2013 and was to be applied retrospectively for all comparative periods presented. The adoption of this guidance had no impact on the Company’s consolidated financial statements.
	In February 2013, the FASB issued ASU No. 2013-02, Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income, an update to ASC Topic 220, Comprehensive Income. This amendment requires entities to provide information about the amounts reclassified out of accumulated other comprehensive income by component. Entities are required to present, either on the face of the statement where net income is present or in the notes, significant amounts reclassified out of accumulated other comprehensive income by the respective line items of net income but only if the amount reclassified is required under GAAP to be reclassified to net income in its entirety in the same reporting period. For other amounts that are not required under GAAP to be reclassified in their entirety to net income, an entity is required to cross-reference to other disclosures required under GAAP that provide additional detail about those amounts. This update became effective for the Company for the fiscal year beginning January 1, 2013 and was applied prospectively. The adoption did not have a material impact on the Company’s consolidated financial statements.
	In July 2013, the FASB issued ASU No. 2013-11, Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists, an update to ASC Topic 740, Income Taxes. This update provides clarification regarding the presentation of an unrecognized tax benefit related to a net operating loss carryforward, a similar tax loss, or a tax credit carryforward. Under this update, the liability related to an unrecognized tax benefit, or a portion thereof, should be presented in the financial statements as a reduction to a deferred tax asset if available under the tax law of the applicable jurisdiction to settle any additional income taxes that would result from the disallowance of a tax position. Otherwise, the unrecognized tax benefit should be presented in the financial statements as a separate liability. The assessment is based on the unrecognized tax benefit and deferred tax asset that exist at the reporting date. The provisions of this update are effective on a prospective basis beginning in 2014 for annual and interim reporting periods. Early adoption is permitted. This update was effective for the Company beginning January 1, 2014. The Company does not expect the adoption of this guidance to have a material impact on its consolidated financial statements.

Net_Loss_Per_Share

Net Loss Per Share	12 Months Ended
	Dec. 31, 2013
Earnings Per Share [Abstract]	'
Earnings Per Share [Text Block]	'
	4. Net Loss Per Share
	Basic net loss per share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of common shares outstanding during the period, without consideration for common stock equivalents. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common share equivalents outstanding for the period determined using the treasury-stock method and the if-converted method. For purposes of this calculation, stock options, warrants and PRSUs are considered to be common stock equivalents and are only included in the calculation of diluted net loss per share when their effect is dilutive.
	The following tables and discussion provide a reconciliation of the numerator and denominator of the basic and diluted net loss per share computations. The calculation below provides net loss, weighted-average common shares outstanding, and the resultant net loss per share on both a basic and diluted basis for the years ended December 31, 2011, 2012 and 2013.
	Historical net loss per share
		Year Ended December 31,
		2011		2012		2013
	Numerator:
	Net loss	$	-40,531,613	$	-17,291,758	$	-18,032,438
	Denominator:
	Weighted-average common shares		29,003,991		35,858,757		36,036,996
	outstanding
	Basic and diluted net loss per share	$	-1.4	$	-0.48	$	-0.5
	As of December 31, 2011, 2012 and 2013 the following number of potential common stock equivalents were outstanding:
	Common stock equivalents
		Year Ended December 31,
		2011	2012			2013
	Outstanding common stock options	2,592,009		3,879,239		5,246,465
	Outstanding warrants	133,968		133,968		34,647
	Outstanding RSUs	271,213		273,988		270,649
	Total	2,997,190		4,287,195		5,551,761
	These common stock equivalents were excluded from the determination of diluted net loss per share due to their anti-dilutive effect on earnings.

Other_Comprehensive_Income_Los

Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2013
Other Comprehensive Income (Loss), Tax [Abstract]	'
Other Comprehensive Income (Loss) [Text Block]	'
	5. Other Comprehensive Income (Loss)
	The accumulated balances related to each component of other comprehensive income (loss) were as follows:
		Foreign Currency				Accumulated Other
		Translation Gains		Unrealized Net Gains		Comprehensive Gains
		(Losses)		(Losses) on Securities		(Losses)
	Balance at December 31,	$	—	$	—	$	—
	2010
	Unrealized gain (loss)		-5,718		-546		-6,264
	Net amount reclassified		—		—		—
	to net loss
	Other comprehensive		-5,718		-546		-6,264
	income (loss)
	Balance at December 31,		-5,718		-546		-6,264
	2011
	Unrealized gain (loss)		707		78,204		78,911
	Net amount reclassified		—		102		102
	to net loss
	Other comprehensive		707		78,306		79,013
	income (loss)
	Balance at December 31,		-5,011		77,760		72,749
	2012
	Unrealized gain (loss)		-6,805		-4,203		-11,008
	Net amount reclassified		—		-5,050		-5,050
	to net loss
	Other comprehensive		-6,805		-9,253		-16,058
	income (loss)
	Balance at December 31,	$	-11,816	$	68,507	$	56,691
	2013
	The assets and liabilities of foreign operations are translated into U.S. dollars using the current exchange rate. For those operations, changes in exchange rates generally do not affect cash flows, which results in translation adjustments being made in stockholders’ equity rather than to net loss.
	Reclassifications Out of Accumulated Other Comprehensive Loss
		Amount Reclassified from		Affected Line Item in the Condensed Consolidated
		Accumulated Other Comprehensive		Statements of Operations and Comprehensive Loss
		Loss
	Details about Accumulated	Year Ended
	Other	December 31, 2013
	Comprehensive Loss
	Components
	Unrealized Net Gains on	$	5,050	Other income (expense)
	Securities
	Total Reclassifications for	$	5,050
	the period

Investments

Investments	12 Months Ended
	Dec. 31, 2013
Investments, Debt and Equity Securities [Abstract]	'
Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]	'
	6. Investments
	The Company applies the fair value measurement and disclosure provisions of ASC Topic 820, Fair Value Measurements and Disclosures (“ASC 820”). ASC 820, which defines fair value, establishes a framework for measuring fair value in GAAP, and expands disclosures about fair value measurements. Investments consist primarily of investments with original maturities greater than three months, but no longer than 24 months when purchased.
	ASC 820 establishes a three-level valuation hierarchy for fair value measurements. These valuation techniques are based upon the transparency of inputs (observable and unobservable) to the valuation of an asset or liability as of the measurement date. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect the Company’s market assumptions. These two types of inputs create the following fair value hierarchy:
	Level 1 — Valuation is based on quoted prices for identical assets or liabilities in active markets.
	Level 2 — Valuation is based on quoted prices for similar assets or liabilities in active markets, or other inputs that are observable for the asset or liability, either directly or indirectly, for the full term of the financial instrument.
	Level 3 — Valuation is based upon other unobservable inputs that are significant to the fair value measurement.
	The fair value of the Company’s fixed income securities is based on a market approach using quoted market values.
	The following table summarizes the fair value of cash and cash equivalents and investments as of December 31, 2012:
	Description	Cost		Level 1		Level 2		Fair Value (Carrying
								Value)
	Cash
	Cash	$	5,227,208	$	5,227,208	$	—	$	5,227,208
	Cash equivalents
	Money market funds		28,769,658		28,769,658		—		28,769,658
	Cash and cash equivalents	$	33,996,866	$	33,996,866	$	—	$	33,996,866
	Short-term investments (due within 1 year)
	U.S. government treasury obligations	$	10,049,323	$	10,053,393	$	—	$	10,053,393
	U.S. government agency obligations		89,824,358		89,847,365		—		89,847,365
	Corporate obligations		41,905,867		—		41,940,065		41,940,065
	Total short-term investments	$	141,779,548	$	99,900,758	$	41,940,065	$	141,840,823
	Long-term investments (due after 1 year
	through 2 years)
	U.S. government treasury obligations	$	5,024,697	$	5,030,699	$	—	$	5,030,699
	U.S. government agency obligations		17,455,606		17,463,067		—		17,463,067
	Corporate obligations		3,043,860		—		3,046,883		3,046,883
	Total long-term investments	$	25,524,163	$	22,493,766	$	3,046,883	$	25,540,649
	The following table summarizes the fair value of cash and cash equivalents and investments as of December 31, 2013:
	Description	Cost		Level 1		Level 2		Fair Value (Carrying
								Value)
	Cash
	Cash	$	7,887,502	$	7,887,502	$	—	$	7,887,502
	Cash equivalents
	Money market funds		44,959,438		44,959,438		—		44,959,438
	Cash and cash equivalents	$	52,846,940	$	52,846,940	$	—	$	52,846,940
	Short-term investments (due within 1 year)
	U.S. government treasury obligations	$	5,009,194	$	5,013,850	$	—	$	5,013,850
	U.S. government agency obligations		33,598,370		33,609,886		—		33,609,886
	Corporate obligations		31,789,117		—		31,810,412		31,810,412
	Total short-term investments	$	70,396,681	$	38,623,736	$	31,810,412	$	70,434,148
	Long-term investments (due after 1 year
	through 2 years)
	U.S. government agency obligations	$	14,807,642	$	14,821,065	$	—	$	14,821,065
	Corporate obligations		10,743,707		—		10,750,594		10,750,594
	Total long-term investments	$	25,551,349	$	14,821,065	$	10,750,594	$	25,571,659
	All securities held at December 31, 2012 and 2013, were classified as available-for-sale as defined by ASC 320.
	Total unrealized gross gains were $79,031 and $76,630 for the years ended December 31, 2012 and 2013, respectively. Total unrealized gross losses were $1,271 and $8,122 for the years ended December 31, 2012 and 2013, respectively. The Company does not consider any of the unrealized losses to be other-than-temporary impairments because the Company has the intent and ability to hold investments until they recover in value.

Property_and_Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2013
Property, Plant and Equipment [Abstract]	'
Property, Plant, and Equipment and Intangible Assets [Text Block]	'
	7. Property and Equipment
	Property and equipment consisted of the following:
				December 31,
		Estimated Useful Lives		2012		2013
	Laboratory equipment		7	$	3,748,201	$	4,796,393
	Office equipment and software		3 – 7		809,146		972,789
	Leasehold improvements		7		216,917		348,901
	Assets not in service				526,495		503,208
					5,300,759		6,621,291
	Less accumulated depreciation				-2,133,854		-2,781,865
				$	3,166,905	$	3,839,426
	Assets not in service represent new laboratory equipment that was not installed and ready to use at December 31, 2012 and 2013. The total amount of depreciation expense for the years ended December 31, 2011, 2012 and 2013 were $262,518, $358,367 and $674,725 respectively.

LongTerm_Debt

Long-Term Debt	12 Months Ended
	Dec. 31, 2013
Debt Disclosure [Abstract]	'
Debt Disclosure [Text Block]	'
	8. Long-Term Debt
	In August, 2010 the Company obtained a $15.0 million loan commitment from Mid Cap Financial (“Mid-Cap”) and Silicon Valley Bank (“SVB”) and borrowed $10.0 million at the time the facility was created. In December 2010, the Company accessed the remaining tranche of $5.0 million. In June 2012, the company terminated the facility, paid the entire outstanding balance and recorded a loss on debt extinguishment of $992,000, which included a 5% prepayment fee of $615,000 and the write off of unamortized deferred financing fees and discounts of $377,000. In connection with the loan during 2010, the Company issued warrants to lenders to purchase an aggregate of 64,674 shares of Series C-3 convertible preferred stock. The fair value of the preferred stock warrants issued was $219,322 on the dates of issuance and was based on observable inputs using quoted market values and the income approach as derived by the Black-Scholes model. The terms of these preferred stock warrants are described in Note 9.
	Interest paid was $1,334,507, $655,834 and $0 for the years ended December 31, 2011, 2012 and 2013, respectively.

Warrants

Warrants	12 Months Ended
	Dec. 31, 2013
Equity [Abstract]	'
Preferred Stock [Text Block]	'
	9. Warrants
	In 2007, the Company issued warrants as consideration in connection with its loan commitment from GECC and Oxford to purchase 69,294 of Series C-3 convertible preferred stock, maturing in 2017. These preferred stock warrants were exercisable upon issuance, and no contingent conversion feature exists. Upon closing of the initial public offering, these warrants were converted to warrants to purchase common stock and were reclassified to stockholders’ equity.
	In August 2010 and December 2010, the Company issued warrants as consideration in connection with its loan commitment from Mid-Cap and SVB to purchase either Series C-3 preferred stock or preferred stock offered in a subsequent offering. The number of preferred stock warrants issued was based on the Series C-3 convertible preferred stock and a $8.12 per share exercise price. The preferred stock warrants will mature in 2020, are exercisable upon issuance and do not contain contingent conversion features. Upon closing of the initial public offering, these warrants were converted to warrants to purchase common stock and were reclassified to stockholders’ equity.
	During 2013, the Company issued 47,791 shares of common stock in connection with the cashless exercise of warrants to purchase stock. As a result, the warrants issued to Oxford, Mid-Cap and SVB were no longer outstanding as of December 31, 2013.

Leases

Leases	12 Months Ended
	Dec. 31, 2013
Leases [Abstract]	'
Leases of Lessee Disclosure [Text Block]	'
	10. Leases
	Future minimum lease payments for noncancellable operating leases as of December 31, 2013, are as follows:
	2014	$	825,810
	2015		143,524
	2016		154,663
	2017		158,474
	2018		26,677
	Thereafter		—
	Total minimum lease payments	$	1,309,148
	Rent expense for operating leases was $421,297, $512,855 and $784,531 for the years ended December 31, 2011, 2012 and 2013, respectively.

Stockholders_Equity_Deficit

Stockholders' Equity (Deficit)	12 Months Ended
	Dec. 31, 2013
Equity [Abstract]	'
Stockholders' Equity Note Disclosure [Text Block]	'
	11. Stockholders’ Equity (Deficit)
	Stock-Based Compensation Plans
	The Company has had stock-based compensation plans since 1997. The awards made under the plans adopted in 1997 and 2007 consisted of stock options. The 2010 Equity Incentive Plan (the “2010 Plan”), which is the only plan under which awards may currently be made, authorizes awards in the form of stock options, stock appreciation rights, restricted stock, PRSUs, performance units and performance shares. Awards under the 2010 Plan may be made to employees, directors and certain consultants as determined by the compensation committee of the board of directors. There were 5,195,563 and 6,625,563 shares of common stock authorized and reserved at December 31, 2012 and December 31, 2013 under these plans, respectively.
	Stock Options
	Under the various plans, employees have been granted incentive stock options, while directors and contractors have been granted non-qualified stock options. The plans allow the holder of an option to purchase common stock at the exercise price, which was at or above the fair value of the Company’s common stock on the date of grant.
	Generally, options granted under the 1997 and 2007 plans in connection with an employee’s commencement of employment vest over a four-year period with one-half of the shares subject to the grant vesting after two years of employment and remaining options vesting monthly over the remainder of the four-year period. Options granted under the 1997 and 2007 plans for performance or promotions vest monthly over a four-year period. Generally, options granted under the 2010 Plan vest annually over a four-year period. Unexercised stock options terminate on the tenth anniversary date after the date of grant. The Company recognizes the stock-based compensation expense over the requisite service period of the individual grantees, which generally equals the vesting period. The Company utilizes a Black-Scholes option-pricing model to estimate the value of stock options. The Black-Scholes model allows the use of a range of assumptions related to volatility, risk-free interest rate, employee exercise behavior and dividend yield. Prior to 2013, since the Company did not have sufficient history as a publicly traded company to evaluate volatility, the Company used an average of several peer companies’ volatilities to determine a reasonable estimate of volatility. Beginning in 2013, the Company utilizes a combination of peer volatility and company volatility. For purposes of identifying peer companies, the Company considered characteristics such as industry, length of trading history, market capitalization and similar product pipelines.
	Due to insufficient history as a public company, the Company is using the “simplified” method for “plain vanilla” options to estimate the expected term of the stock options grants. Under this approach, the weighted-average expected life is presumed to be the average of the vesting term and the contractual term of the option. The risk-free interest rate assumption is derived from the weighted-average yield of a Treasury security with the same term as the expected life of the options, and the dividend yield assumption is based on historical experience and the Company’s estimate of future dividend yields.
	The weighted-average value of the individual options granted during 2011, 2012 and 2013 were determined using the following assumptions:
		Year Ended December 31,
		2011				2012			2013
	Weighted-average volatility			82.77	%		89.13	%			101	%
	Risk-free interest rate			2.27	%		1.1	%			1.31	%
	Weighted-average expected life (in years)			6.2			6.2				6.6
	Dividend yield			0	%		0	%			0	%
	The resulting value of options granted was $5,098,734 and $13,725,956 for the years ended December 31, 2012 and 2013, respectively, which will be amortized into income over the remaining requisite service period. The Company recognized stock-based compensation cost, net of forfeitures, in the amount of $1,960,345, $3,022,693 and $6,059,005 for the years ended December 31, 2011, 2012 and 2013, respectively. The Company’s stock option activity and related information are summarized as follows:
			Options		Weighted-Average			Weighted-Average Remaining		Aggregate
					Exercise Price			Contractual Term (In Years)		Intrinsic
										Value
	Outstanding at		2,019,333		$	2.82
	January 1, 2011
	Granted during year		926,956			9.39
	Exercised during year		-283,061			2.1
	Expired during year		-23,039			7.64
	Forfeited during year		-48,180			7.07
	Outstanding at		2,592,009		$	5.12		7.38		$	1,652,483
	December 31, 2011
	Exercisable at		1,339,341			2.69		5.97			1,523,957
	December 31, 2011
	Outstanding at		2,592,009		$	5.12
	January 1, 2012
	Granted during year		1,492,395			4.61
	Exercised during year		-134,534			2.91
	Expired during year		-13,502			9.86
	Forfeited during year		-57,129			6.68
	Outstanding at		3,879,239		$	4.96		7.5		$	16,198,044
	December 31, 2012
	Exercisable at		1,676,016			3.83		5.72			8,882,339
	December 31, 2012
	Outstanding at		3,879,239			4.96
	January 1, 2013
	Granted during year		1,566,062			10.79
	Exercised during year		-188,699			3.42
	Expired during year		—
	Forfeited during year		-10,137			6.04
	Outstanding at		5,246,465		$	6.76		7.39		$	22,002,357
	December 31, 2013
	Exercisable at		2,269,438			4.59		5.73			13,968,005
	December 31, 2013
	The following is a rollforward of the Company’s nonvested stock options from January 1, 2011 to December 31, 2013.
			Options		Weighted-Average Grant Date Value
	Nonvested stock options at January 1, 2011		748,107		$	1.97
	Granted during year		926,956			6.83
	Vested during year		-330,132			1.97
	Expired during year		-44,083			5.22
	Forfeited during year		-48,180			4.81
	Nonvested at December 31, 2011		1,252,668		$	5.34
	Nonvested stock options at January 1, 2012		1,252,668		$	5.34
	Granted during year		1,492,395			3.42
	Vested during year		-484,711			4.51
	Expired during year		—			—
	Forfeited during year		-57,129			4.61
	Nonvested at December 31, 2012		2,203,223		$	4.24
	Nonvested stock options at January 1, 2013		2,203,223		$	4.24
Granted during year		1,566,062			8.76
Vested during year		-782,121			4.22
Expired during year		—			—
Forfeited during year		-10,137			4.58
Nonvested at December 31, 2013		2,977,027		$	6.62
The total grant date value of options vested during 2011, 2012 and 2013 was $650,068, $2,216,038 and $3,303,701, respectively. As of December 31, 2012 and December 31, 2013, the total remaining unrecognized compensation cost related to nonvested stock options granted was $6,719,346 and $13,900,183, respectively, which will be amortized over the remaining requisite service period. The intrinsic value of options exercised was $511,790 and $1,884,651 for the years ended December 31, 2012 and December 31, 2013, respectively.
Restricted Stock Units
In May 2011, the Company adopted and granted awards under a performance-based RSU program (the “2011 PRSU Program”) under the 2010 Plan. Each unit represents an amount equal to one share of the Company’s common stock. The PRSUs will be earned, in whole or in part, based on performance and service conditions. The performance condition is based upon whether the Company receives regulatory approval to sell a therapeutic product, and the awards include a target number of PRSUs that will vest upon a First Commercial Approval, and a maximum number of PRSUs that will vest upon a Second Commercial Approval. Any earned PRSUs will vest fifty percent based on the performance condition of commercial approval and fifty percent one year thereafter to fulfill the service condition, which requires the employee to remain employed by the Company.
As of December 31, 2013, the Company had 270,649 PRSU awards outstanding. The unrecorded stock compensation expense is based on number of units granted, less estimated forfeitures based on the Company’s historical forfeiture rate of 6.49%, and the closing market price of the Company’s common stock at the grant date. As of December 31, 2013, the performance condition of obtaining regulatory approval had not been achieved, therefore, no vesting had occurred. The awards are being accounted for under ASC 718, and compensation expense is to be recorded if the Company determines that it is probable that the performance conditions will be achieved. As of December 31, 2013, it was not probable that the performance conditions will be achieved, therefore, no compensation expense related to the PRSUs was recorded for the year ended December 31, 2013. Unrecorded compensation expense for the 2011 PRSU program as of December 31, 2013 was $2.7 million.
Employee Stock Purchase Plan
Effective January 1, 2014, the Company implemented its 2010 Employee Stock Purchase Plan, pursuant to which the Company’s eligible employees can purchase shares of the Company’s common stock at a discount.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'
Income Tax Disclosure [Text Block]	'
	12. Income Taxes
	A reconciliation of the expected income tax benefit (expense) computed using the federal statutory income tax rate to the Company’s effective income tax rate is as follows for years ended December 31, 2011, 2012, and 2013:
		December 31,
		2011		2012		2013
	Income tax computed at federal statutory tax rate	34	%	34	%	34	%
	State taxes, net of federal benefit	0.3	%	3.9	%	4.2	%
	International operations	-0.1	%	-0.2	%	-2.1	%
	Research and development credits	4	%	2.4	%	13.8	%
	Orphan drug credits	0	%	0	%	8.3	%
	Permanent differences	0.2	%	-2.2	%	-5.4	%
	Other	0	%	-0.2	%	-0.1	%
	Change in valuation allowance	-38.4	%	-37.7	%	-52.7	%
	Total	0	%	0	%	0	%
	At December 31, 2013, the Company has net operating loss carryforwards totaling approximately $163,200,000 and $214,700,000 for federal and state income taxes, respectively, that may be used to offset future taxable income. If not used, the carryforwards will begin expiring in the year 2022. The Company has determined that it experienced a change in ownership as defined under Section 382 of the U.S. Internal Revenue Code (the “Code”), as a result of the public offering in August 2011. As a result, the future use of its net operating losses, after giving effect to net unrealized built-in gains, will be limited to approximately $94,200,000 for 2013, $39,000,000 per year for the years 2014 and 2015, $29,700,000 for 2016 and $16,800,000 for 2017. Any available but unused amounts will become available for use in all successive years.
	Net deferred tax assets and liabilities are comprised of the following:
		December 31,
		2012			2013
	Deferred tax assets
	Net operating loss carryforwards	$	53,754,000		$	65,678,000
	Research and development credit carryforwards		7,110,000			9,592,000
	Orphan Drug Credit		—			1,495,000
	Stock Options		1,045,000			2,377,000
	Deferred revenue		5,355,000			—
	Other		91,000			120,000
	Deferred tax assets		67,355,000			79,262,000
	Deferred tax liabilities
	Deferred Revenue		—			-2,594,000
	Property and equipment		-143,000			-241,000
	Deferred tax liabilities	$	-143,000		$	-2,835,000
	Net deferred tax asset before valuation allowance	$	67,212,000		$	76,427,000
	Less valuation allowance		-67,212,000			-76,427,000
	Net deferred tax assets	$	—		$	—

Collaborations

Collaborations	12 Months Ended
	Dec. 31, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Collaborative Arrangement Disclosure [Text Block]	'
	13. Collaborations
	In October 2007, the Company entered into an exclusive worldwide license with R&D Biopharmaceuticals to research, develop, and commercialize products containing conjugates of folate receptor targeting compounds and tubulysin compounds. The Company paid an upfront fee of $300,000 as research and development and has since paid $50,000 in annual maintenance fees and $100,000 in 2013 for dosing the first human patient with folate tubulysin. In February 2011, this licensing agreement was assigned by R&D Biopharmaceuticals to Trientlgasse. The Company could pay $6,300,000 in additional contingent payments upon the achievement of specific scientific, clinical, and regulatory milestones, in addition to royalties upon commercial sales. All payments have been expensed as research and development as incurred, as there is no alternate future use for this technology.
	In December 1995, as amended in October 1998, the Company entered into an exclusive license agreement with Purdue Research Foundation, which licenses the right under certain patents to the Company. The Company is obligated to pay an annual minimum royalty of $12,500 until commercial sales commence, following which time the payment of single digit royalty rates will commence. All payments have been expensed as incurred, as the Company does not believe there is an alternate future use for this technology.
	In December 2009, the Company entered into a financial term sheet to be incorporated into a written license agreement with Purdue Research Foundation for a patent related to prostate cancer. The agreement was signed and became effective on March 1, 2010. Pursuant to the exclusive license agreement, the Company is subject to annual payments of $15,000, payable until first commercial sale, following which time the payment of single digit royalty rates will commence. In addition, certain clinical and regulatory milestone payments of $500,000 along with sales-based milestones related to third-party sales are also payable. The Company is also subject to penalties totaling $300,000 if certain diligence milestones are not met. Subsequent to the first commercial sales, the annual milestone is $100,000. Future milestone payments in excess of $500,000 may be waived by Purdue Research Foundation.
	Merck Collaboration Agreement
	In April 2012, the Company entered into a worldwide collaboration agreement with Merck regarding the development and commercialization of vintafolide. The agreement grants Merck worldwide rights to develop and commercialize vintafolide and the right to use etarfolatide. The Company received a $120.0 million non-refundable upfront payment and a $5.0 million milestone payment in 2012 and is eligible for additional milestone payments of up to $875.0 million based on the successful achievement of development, regulatory and commercialization goals for vintafolide in a total of six different cancer indications. The milestones that could potentially be reached in 2014 are for the commencement of the first Phase 3 clinical trial in NSCLC and if we receive marketing authorization in the European Union for vintafolide for the treatment of PROC. In addition, in the event of regulatory approval and launch of vintafolide, the Company will split U.S. earnings under the collaboration arrangement on a 50/50 basis with Merck and will receive a double-digit percentage royalty on sales of the product in the rest of the world. The Company has retained the right (which it can opt out of) to co-promote vintafolide with Merck in the U.S. and Merck has the exclusive right to promote vintafolide in the rest of the world. The Company is responsible for the majority of funding and completion of the ongoing Phase 3 PROCEED clinical trial of vintafolide for the treatment of patients with platinum resistant ovarian cancer. The Company is responsible for the execution of the Phase 2b TARGET trial of vintafolide for the treatment of second line non-small cell lung cancer. Merck is responsible for the costs of the TARGET trial and for all other development activities and costs and will have all decision rights with respect to the development and commercialization of vintafolide. The Company is responsible for the development, manufacture and commercialization worldwide of etarfolatide.
	For revenue recognition purposes, the Company viewed the collaboration with Merck as a multiple element arrangement. Multiple element arrangements are analyzed to determine whether the various performance obligations, or elements, can be separated or whether they must be accounted for as a single unit of accounting. The Company evaluated whether the delivered elements under the arrangement have value on a stand-alone basis and whether objective and reliable evidence of fair value of the undelivered element exists. Deliverables that do not meet these criteria are not evaluated separately for the purpose of revenue recognition. For a single unit of accounting, payments received are recognized in a manner consistent with the final deliverable. The Company has determined that the deliverables related to the collaboration with Merck, including the licenses granted to Merck, as well as the Company performance obligations to provide various research and development services, will be accounted for as a single unit of account. This determination was made because the successful development of the therapeutic drug, vintafolide, is dependent on the companion diagnostic, etarfolatide, to select patients who are most likely to receive the most benefit from vintafolide. Given the nature of the combined benefit of the companion diagnostic and the therapeutic drug, the ongoing research and development services to be provided by the Company are essential to the overall arrangement as the Company has significant knowledge and technical know-how that is important to realizing the value of the licenses granted. The performance period over which the revenue will be recognized continues from the date of execution of the agreement through the end of 2014, when the Company expects to be completed with the various trials that are specified in the collaboration agreement and the Company’s performance obligations will be completed. The Company will continue to review the timing of when the various trials will be completed in order to assess that the estimated performance period over which the revenue is to be recognized is appropriate. Any significant changes in the timing of the performance period could result in a change in the revenue recognition period.
	The Company is recognizing the non-refundable $120.0 million upfront payment and funding from the research and development services on a straight-line basis over the performance period. The Company recognized approximately $34.7 million and $64.9 million of collaboration revenue during 2012 and 2013 respectively, and had deferred revenue related to the collaboration of approximately $104.0 million and $59.7 million at December 31, 2012 and December 31, 2013 respectively. As future research and development services are performed and become billable, the Company will utilize a cumulative catch-up approach for purposes of recognizing the consideration on a straight-line basis. Though accounted for as a single unit of account for presentation purposes, the Company has made an allocation of revenue recognized as collaboration revenue between the license and the services. This allocation is based upon the relative selling price of each deliverable. License revenue was approximately $27.5 million and $51.5 million while research and development services were approximately $7.2 million and $13.4 million of the collaboration revenue for the years ended December 31, 2012 and 2013, respectively.
	The collaboration arrangement with Merck includes milestone payments of approximately $880.0 million. These milestones consist of development milestones of approximately $380.0 million and sales-based milestones of approximately $500.0 million. The development milestones range from $5.0 million to $45.0 million each and are based on the commencement of a new phase of clinical trials for specific indications, filing for approval in the U.S. or major countries in Europe for specific indications and approval in the U.S. and other major countries. The Company evaluated each of these milestone payments and believes that all but one of the milestones are substantive as there is substantial performance risk that must occur in order for them to be met as it must complete additional clinical trials which show a positive outcome or receive approval from a regulatory authority and would be commensurate with the enhancement of value of the underlying intellectual property. The non-substantive milestone is $5.0 million and was received in the fourth quarter of 2012. This milestone payment of $5.0 million is being combined with the other consideration received in the arrangement, being the license and research and development reimbursements, and under the cumulative catch-up approach is being recognized on a straight-line basis over the performance period. The $500.0 million of sales-based milestones will occur after development milestones are achieved, and the Company will account for these in the same manner as royalties. The sales-based milestones would be achieved if certain sales thresholds are exceeded for worldwide sales of vintafolide and etarfolatide. To date, the products have not been approved and no revenue has been recognized related to the earnings split on U.S sales, development milestones, sales-based milestones or royalties.
	Merck has the right to terminate the collaboration agreement on 90 days notice. Merck and the Company each have the right to terminate the agreement due to the material breach or insolvency of the other party. The Company has the right to terminate the agreement in the event that Merck challenges an Endocyte patent right relating to vintafolide. Upon termination of the agreement, depending upon the circumstances, the parties have varying rights and obligations with respect to the continued development and commercialization of vintafolide and, in the case of termination for cause by Merck, certain royalty obligations and U.S. profit and loss sharing.
	NMP License and Commercialization Agreement
	In August 2013, the Company entered into a license and commercialization agreement with Nihon Medi-Physic Co., LTD. (“NMP”) that grants NMP the right to develop and commercialize etarfolatide in Japan for use in connection with vintafolide in Japan. The Company received a $1.0 million non-refundable upfront payment, is eligible for up to $4.5 million based on the successful achievement of regulatory goals for etarfolatide in five different cancer indications and is eligible to receive double-digit percentage royalties on sales of etarfolatide in Japan.
	For revenue recognition purposes, the Company viewed the agreement with NMP as a multiple element arrangement. Multiple element arrangements are analyzed to determine whether the various performance obligations, or elements, can be separated or whether they must be accounted for as a single unit of accounting. The Company has identified the deliverables related to the collaboration with NMP, which include the license granted to NMP, as well as the obligation to provide preclinical and clinical supply of etarfolatide, to provide rights to NMP if a product is developed that replaces etarfolatide, obligation for the Company to provide clinical data to NMP during the contract period and coordination of development and commercialization efforts between Merck for vintafolide and NMP for etarfolatide in Japan. The Company’s deliverables will be accounted for as a single unit of account, therefore the non-refundable upfront payment will be recognized on a straight-line basis over the performance period. This determination was made because the successful development of etarfolatide in Japan requires the ongoing participation by the Company, including coordination with Merck and the development of the related therapeutic drug, vintafolide. The performance period over which the revenue will be recognized continues from the date of execution of the agreement through the end of 2033, the estimated termination date of the contract which is when the Company’s performance obligations will be completed. Any significant changes in the timing of the performance period could result in a change in the revenue recognition period. The Company had deferred revenue related to the agreement of approximately $0.9 million at December 31, 2013.
	The arrangement with NMP includes milestone payments of up to approximately $4.5 million and the milestones are based on the commencement of clinical trials in Japan for specific and non-specific indications and filing for approval in Japan for specific and non-specific indications. The Company evaluated each of these milestone payments and believes that all of the milestones are substantive as there is substantial performance risk that must occur in order for them to be met because the Company must complete additional clinical trials which show a positive outcome or receive approval from a regulatory authority and would be commensurate with the enhancement of value of the underlying intellectual property. To date, the products have not been approved in Japan and no revenue has been recognized related to the regulatory milestones or royalties.
	NMP has the right to terminate the collaboration agreement on 90 days notice prior to first commercial sale in Japan and six months notice after the first commercial sale in Japan. NMP also has the right to terminate the agreement on six months notice if the Company and/or Merck fail to launch vintafolide after receiving regulatory approval in Japan. NMP and the Company each have the right to terminate the agreement due to the material breach or insolvency of the other party. Upon termination of the agreement depending on the circumstances, the parties have varying rights and obligations with respect to licensing and related regulatory materials and data.

RelatedParty_Transactions

Related-Party Transactions	12 Months Ended
	Dec. 31, 2013
Related Party Transactions [Abstract]	'
Related Party Transactions Disclosure [Text Block]	'
	14. Related-Party Transactions
	The Company funds research at the employer of one of its founders and current Chief Science Officer. Amounts included in research and development expenses were $517,500, $788,737 and $824,559, for the years ended December 31, 2011, 2012 and 2013, respectively.
	In September 2011, the Company entered into exclusive worldwide licenses with On Target Laboratories, L.L.C. (“On Target”) to develop and commercialize products relating to the compound comprising the Company’s Folate and DUPA ligands and other certain Licensed Patents. On Target’s Chief Executive Officer is the brother of the Company’s Chief Science Officer. The Company believes that the terms of the agreement are no less favorable than terms that would have been available in an arm’s length transaction. On Target is solely responsible for conducting research and development, seeking regulatory approval and commercialization of products. The Company received nonrefundable upfront license fees totaling $191,000 from On Target in December 2011. The Company has determined that the deliverables under this agreement do not meet the criteria required for separate accounting units for the purposes of revenue recognition, and as a result, the Company recognized revenue from non-refundable, upfront fees when the performance condition of delivering the licenses and certain consultation services had been achieved and there was reasonable assurance of collectability. If On Target fails to meet minimum spend requirements on research and development, the Company has the right to terminate the agreement. The Company will be entitled to receive minimum royalty payments annually based on net sales, but there is no guarantee that a commercial product will be developed and approved for commercial sales. The Company will also be entitled to reimbursement of expenses relating to patent expenses and payments to the inventors and Purdue University if certain milestones are met. During 2011, the Company received a $50,000 reimbursement from On Target for payments made to inventors for issued patents. During each of 2012 and 2013, the Company received $20,000 in annual maintenance license fees and received $54,475 and $27,394 for reimbursable research and development expenses, for 2012 and 2013, respectively.

Retirement_Plans

Retirement Plans	12 Months Ended
	Dec. 31, 2013
Compensation and Retirement Disclosure [Abstract]	'
Pension and Other Postretirement Benefits Disclosure [Text Block]	'
	15. Retirement Plans
	The Company maintains a 401(k) retirement savings plan to provide retirement benefits for substantially all of its employees. Participants in the plan may elect to contribute a portion of their annual compensation to the plan, limited to the maximum allowed by the Code. Prior to January 1, 2014 the Company did not match 401(k) contributions. Effective January 1, 2014, the Company has implemented a matching contribution for the 401k contributions.

Selected_Quarterly_Financial_D

Selected Quarterly Financial Data (unaudited)	12 Months Ended
	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]	'
Quarterly Financial Information [Text Block]	'
	16. Selected Quarterly Financial Data (unaudited)
	The following table summarizes the unaudited statements of operations for each quarter of 2013 and 2012 (in thousands except share and per share amounts):
			Quarters Ended
			March 31		June 30		September 30		December 31
	2013
	Revenue		$	14,514	$	16,483	$	16,600	$	17,274
	Operating Expenses:
	Research and development			12,259		18,607		13,501		13,533
	General and administrative			6,256		6,211		6,143		6,704
	Loss from operations			-4,001		-8,335		-3,044		-2,963
	Interest, net			139		126		111		89
	Other			—		-18		-108		-28
	Net loss		$	-3,862	$	-8,227	$	-3,041	$	-2,902
	Basic and diluted net loss per share(1)		$	-0.11	$	-0.23	$	-0.08	$	-0.08
	Weighted average common shares			35,930,265		35,991,402		36,077,440		36,146,061
	outstanding – basic and diluted(2)
			Quarters Ended
			March 31		June 30		September 30		December 31
	2012
	Revenue		$	—	$	7,813	$	12,415	$	14,454
	Operating Expenses:
	Research and development			6,417		8,806		9,930		10,518
	General and administrative			3,094		3,195		3,815		4,950
	Loss from operations			-9,511		-4,188		-1,330		-1,014
	Interest, net			-334		-252		95		190
	Other			75		-994		-4		-25
	Net loss		$	-9,770	$	-5,434	$	-1,239	$	-849
	Basic and diluted net loss per share(1)		$	-0.27	$	-0.15	$	-0.03	$	-0.02
	Weighted average common shares			35,798,530		35,843,312		35,881,112		35,910,490
	outstanding – basic and diluted(2)
		-1	Per common share amounts for the quarters and full years have been calculated separately. Accordingly, the sum of quarterly amounts may not equal the annual amount because of differences in the weighted average common shares outstanding during each period, principally due to the effect of share issuances by the Company during the year.
		-2	Diluted weighted average common shares outstanding are identical to basic weighted average common shares outstanding and diluted net loss per share is identical to basic net loss per share for all quarters of 2013 and 2012 because common share equivalents are excluded from the calculations of diluted weighted average common shares outstanding for those quarters, as their effect is anti-dilutive.

Significant_Accounting_Policie1

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Stock Split [Policy Text Block]	'
	Stock Split
	On January 10, 2011, the Company effected a 1.00 for 1.91 reverse stock split. All historical common stock and per share information has been changed to reflect the stock split.
Basis of Accounting, Policy [Policy Text Block]	'
	Basis of Presentation
	The accompanying consolidated financial statements include the accounts of Endocyte, Inc. and its subsidiaries and all intercompany amounts have been eliminated. The consolidated financial statements are prepared in conformity with U.S. generally accepted accounting principles (“GAAP”). Subsequent events have been evaluated through the date of issuance, which is the same as the date this Form 10-K is filed with the Securities and Exchange Commission.
Use of Estimates, Policy [Policy Text Block]	'
	Use of Estimates
	The preparation of financial statements in conformity with GAAP requires the Company’s management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual amounts may differ from those estimates.
Cash and Cash Equivalents, Policy [Policy Text Block]	'
	Cash and Cash Equivalents
	The Company considers cash and all highly liquid investments with an original maturity of three months or less at the date of purchase to be cash equivalents. Cash equivalents consist primarily of money market instruments that are maintained by an investment manager.
Investment, Policy [Policy Text Block]	'
	Investments
	Investments consist primarily of investments in U.S. Treasuries, U.S. Government agency obligations and corporate debt securities, which could also include commercial paper, that are maintained by an investment manager. Management determines the appropriate classification of marketable securities at the time of purchase and reevaluates such classification as of each balance sheet date. Available-for-sale securities are carried at fair value, with the unrealized gains and losses reported in other comprehensive income. Realized gains and losses and declines in value judged to be other-than-temporary on available-for-sale securities are included in other income. The Company considers and accounts for other-than-temporary impairments according to the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 320, Investments — Debt and Equity Securities (“ASC 320”). The cost of securities sold is based on the specific-identification method. Discounts and premiums on debt securities are amortized to interest income and expense over the term of the security.
Property, Plant and Equipment, Policy [Policy Text Block]	'
	Property and Equipment
	Property and equipment are stated at cost and are being depreciated using the straight-line method over estimated useful lives, which range from three to seven years.
Licenses and Patents [Policy Text Block]	'
	Licenses and Patents
	Licenses and patent costs are expensed as incurred as the Company does not believe there is an alternate future use for the costs. Licenses are classified as research and development and patents are classified as general and administrative expenses in the consolidated statements of operations.
Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block]	'
	Long-Lived Assets
	The Company reviews long-lived assets, including property and equipment, for impairment when events or changes in business conditions indicate that their full carrying value may not be fully recoverable.
Lease, Policy [Policy Text Block]	'
	Leases
	The Company evaluates all leases to determine whether they should be accounted for as operating or capital leases.
Revenue Recognition, Policy [Policy Text Block]	'
	Revenue Recognition
	The Company recognizes revenues from license and collaboration agreements when persuasive evidence of an arrangement exists, delivery has occurred or services have been rendered, the fee is fixed or determinable, and there is reasonable assurance that the related amounts are collectible in accordance with ASC Topic 605, Revenue Recognition (“ASC 605”). The Company’s license and collaboration agreements may contain multiple elements, including grants of licenses to intellectual property rights, agreement to provide research and development services and other deliverables. The deliverables under such arrangements are evaluated under ASC Subtopic 605-25, Multiple-Element Arrangements. Effective January 1, 2011, the Company adopted an accounting standard update that amended the guidance on accounting for arrangements with multiple deliverables. Pursuant to the new standard, each required deliverable is evaluated to determine whether it qualifies as a separate unit of accounting based on whether the deliverable has “stand-alone value” to the customer. The arrangement’s consideration that is fixed or determinable, excluding contingent milestone payments, is then allocated to each separate unit of accounting based on the relative selling price of each deliverable. In general, the consideration allocated to each unit of accounting is recognized as the related goods or services are delivered, limited to the consideration that is not contingent upon future deliverables.
	Upfront payments for licensing the Company's intellectual property are evaluated to determine if the licensee can obtain stand-alone value from the license separate from the value of the research and development services and other deliverables in the arrangement to be provided by the Company. If the Company determines that the license does not have stand-alone value separate from the research and development services or other deliverables, the license, services and other deliverables are combined as one unit of account and upfront payments are recorded as deferred revenue in the balance sheet and are recognized in a manner consistent with the final deliverable. When stand-alone value is identified, the related consideration is recorded as revenue in the period in which the license or other intellectual property rights are delivered.
	In those circumstances where research and development services or other deliverables are combined with the license, and multiple services are being performed such that a common output measure to determine a pattern of performance cannot be discerned, the Company recognizes amounts received on a straight line basis over the performance period. Such amounts are recorded as collaboration revenue. Any subsequent reimbursement payments, which are contingent upon the Company’s future research and development expenditures, will be recorded as collaboration revenue and will be recognized on a straight-line basis over the performance period using the cumulative catch up method. The costs associated with these activities are reflected as a component of research and development expense in the statements of operations in the period incurred.
	Milestone payments under collaborative arrangements are triggered either by the results of the Company’s research and development efforts, achievement of regulatory goals or by specified sales results by a third-party collaborator. Milestones related to the Company’s development-based activities may include initiation of various phases of clinical trials and applications and acceptance for product approvals by regulatory agencies. Due to the uncertainty involved in meeting these development-based milestones, the determination is made at the inception of the collaboration agreement whether the development-based milestones are considered to be substantive (i.e. not just achieved through passage of time). In addition, the amounts of the payments assigned thereto are considered to be commensurate with the enhancement of the value of the delivered intellectual property as a result of the Company’s performance. Because the Company’s involvement is necessary to the achievement of development-based milestones, the Company would account for development-based milestones as revenue upon achievement of the substantive milestone events. Milestones related to sales-based activities may be triggered upon events such as first commercial sale of a product or when sales first achieve a defined level. Since these sales-based milestones would be achieved after the completion of the Company’s development activities, the Company would account for the sales-based milestones in the same manner as royalties, with revenue recognized upon achievement of the milestone.
	Royalties based on reported sales of licensed products will be recognized based on contract terms when reported sales are reliably measurable and collectability is reasonably assured. To date, none of the Company's products have been approved and therefore the Company has not earned any royalty revenue from product sales. In territories where the Company and the collaborator will share profit, the revenue will be recorded in the period earned.
Research and Development Expense, Policy [Policy Text Block]	'
	Research and Development Expenses
	Research and development expenses represent costs associated with the ongoing development of SMDCs and companion imaging agents and include salaries, supplies, and expenses for clinical trials. The Company records accruals for clinical trial expenses based on the estimated amount of work completed. The Company monitors patient enrollment levels and related activities to the extent possible through internal reviews, correspondence, and discussions with research organizations.
	Upfront payments made in connection with business collaborations and research and development arrangements are evaluated under ASC Subtopic 730-20, Research and Development Arrangements. Upfront payments made in connection with business development collaborations are expensed as research and development costs, as the assets acquired do not have alternative future use. Amounts related to future research and development are capitalized as prepaid research and development and are expensed over the service period based upon the level of services provided. As of December 31, 2013, the Company had approximately $2.3 million of capitalized research and development costs included in prepaid expenses and other noncurrent assets.
Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block]	'
	Stock-Based Compensation
	The Company accounts for its stock options pursuant to ASC Topic 718, Compensation — Stock Compensation (“ASC 718”), which requires the recognition of the fair value, or calculated value for nonpublic entities, of stock-based compensation in net income. Stock-based compensation consists of stock options, which are granted at exercise prices at or above the fair market value of the Company’s common stock on the dates of grant. The Company has issued performance based restricted stock units (“PRSUs”) for which stock-based compensation expense will be recognized when the Company determines that it is probable that the performance conditions will be achieved. The Company used the calculated value method to measure its stock-based compensation prior to its initial public offering. The Company recognizes compensation cost based on the grant-date value estimated in accordance with the provisions of ASC 718.
Earnings Per Share, Policy [Policy Text Block]	'
	Net Loss Per Share
	The Company calculates basic net loss per share based on the weighted-average number of outstanding common shares. The Company calculates diluted net loss per share based on the weighted-average number of outstanding common shares plus the effect of dilutive securities.
Regulatory Income Taxes, Policy [Policy Text Block]	'
	Income Taxes
	The Company accounts for income taxes under the liability method in accordance with the provision of ASC Topic 740, Income Taxes (“ASC 740”). ASC 740 requires recognition of deferred taxes to provide for temporary differences between financial reporting and tax basis of assets and liabilities. Deferred taxes are measured using enacted tax rates expected to be in effect in a year in which the basis difference is expected to reverse. The Company continues to record a valuation allowance for the full amount of deferred tax assets, which would otherwise be recorded for tax benefits relating to operating loss and tax credit carryforwards, as realization of such deferred tax assets cannot be determined to be more likely than not.
	The Company accounts for uncertain income tax positions recognized in the financial statements in accordance with Accounting Standards Update (“ASU”) No. 2009-06. This guidance prescribes a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return and provides guidance on derecognition of tax benefits, classification on the balance sheet, interest and penalties, accounting in interim periods, disclosure, and transition.
Segment Reporting, Policy [Policy Text Block]	'
	Segment Information
	Operating segments are defined as components of an enterprise engaging in business activities for which discrete financial information is available and regularly reviewed by the chief operating decision maker in deciding how to allocate resources and in assessing performance. The Company is performing clinical trials globally and has established a subsidiary in The Netherlands to assist in the administration of filing applications with the EMA and a subsidiary in Switzerland for pre-commercial planning activities in Europe. All long-lived assets are held in the U.S. The Company views its operations and manages its business in one operating segment.

Net_Loss_Per_Share_Tables

Net Loss Per Share (Tables)	12 Months Ended
	Dec. 31, 2013
Earnings Per Share [Abstract]	'
Schedule of Calculation of Numerator and Denominator in Earnings Per Share [Table Text Block]	'
	The following tables and discussion provide a reconciliation of the numerator and denominator of the basic and diluted net loss per share computations. The calculation below provides net loss, weighted-average common shares outstanding, and the resultant net loss per share on both a basic and diluted basis for the years ended December 31, 2011, 2012 and 2013.
	Historical net loss per share
		Year Ended December 31,
		2011		2012		2013
	Numerator:
	Net loss	$	-40,531,613	$	-17,291,758	$	-18,032,438
	Denominator:
	Weighted-average common shares		29,003,991		35,858,757		36,036,996
	outstanding
	Basic and diluted net loss per share	$	-1.4	$	-0.48	$	-0.5
Schedule of Weighted Average Number of Shares [Table Text Block]	'
	As of December 31, 2011, 2012 and 2013 the following number of potential common stock equivalents were outstanding:
	Common stock equivalents
		Year Ended December 31,
		2011	2012			2013
	Outstanding common stock options	2,592,009		3,879,239		5,246,465
	Outstanding warrants	133,968		133,968		34,647
	Outstanding RSUs	271,213		273,988		270,649
	Total	2,997,190		4,287,195		5,551,761

Other_Comprehensive_Income_Los1

Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2013
Other Comprehensive Income (Loss), Tax [Abstract]	'
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	'
	The accumulated balances related to each component of other comprehensive income (loss) were as follows:
		Foreign Currency				Accumulated Other
		Translation Gains		Unrealized Net Gains		Comprehensive Gains
		(Losses)		(Losses) on Securities		(Losses)
	Balance at December 31,	$	—	$	—	$	—
	2010
	Unrealized gain (loss)		-5,718		-546		-6,264
	Net amount reclassified		—		—		—
	to net loss
	Other comprehensive		-5,718		-546		-6,264
	income (loss)
	Balance at December 31,		-5,718		-546		-6,264
	2011
	Unrealized gain (loss)		707		78,204		78,911
	Net amount reclassified		—		102		102
	to net loss
	Other comprehensive		707		78,306		79,013
	income (loss)
	Balance at December 31,		-5,011		77,760		72,749
	2012
	Unrealized gain (loss)		-6,805		-4,203		-11,008
	Net amount reclassified		—		-5,050		-5,050
	to net loss
	Other comprehensive		-6,805		-9,253		-16,058
	income (loss)
	Balance at December 31,	$	-11,816	$	68,507	$	56,691
	2013
Schedule of Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block]	'
	Reclassifications Out of Accumulated Other Comprehensive Loss
		Amount Reclassified from		Affected Line Item in the Condensed Consolidated
		Accumulated Other Comprehensive		Statements of Operations and Comprehensive Loss
		Loss
	Details about Accumulated	Year Ended
	Other	December 31, 2013
	Comprehensive Loss
	Components
	Unrealized Net Gains on	$	5,050	Other income (expense)
	Securities
	Total Reclassifications for	$	5,050
	the period

Investments_Tables

Investments (Tables)	12 Months Ended
	Dec. 31, 2013
Investments, Debt and Equity Securities [Abstract]	'
Schedule of Cash, Cash Equivalents and Short-term Investments [Table Text Block]	'
	The following table summarizes the fair value of cash and cash equivalents and investments as of December 31, 2012:
	Description	Cost		Level 1		Level 2		Fair Value (Carrying
								Value)
	Cash
	Cash	$	5,227,208	$	5,227,208	$	—	$	5,227,208
	Cash equivalents
	Money market funds		28,769,658		28,769,658		—		28,769,658
	Cash and cash equivalents	$	33,996,866	$	33,996,866	$	—	$	33,996,866
	Short-term investments (due within 1 year)
	U.S. government treasury obligations	$	10,049,323	$	10,053,393	$	—	$	10,053,393
	U.S. government agency obligations		89,824,358		89,847,365		—		89,847,365
	Corporate obligations		41,905,867		—		41,940,065		41,940,065
	Total short-term investments	$	141,779,548	$	99,900,758	$	41,940,065	$	141,840,823
	Long-term investments (due after 1 year
	through 2 years)
	U.S. government treasury obligations	$	5,024,697	$	5,030,699	$	—	$	5,030,699
	U.S. government agency obligations		17,455,606		17,463,067		—		17,463,067
	Corporate obligations		3,043,860		—		3,046,883		3,046,883
	Total long-term investments	$	25,524,163	$	22,493,766	$	3,046,883	$	25,540,649
	The following table summarizes the fair value of cash and cash equivalents and investments as of December 31, 2013:
	Description	Cost		Level 1		Level 2		Fair Value (Carrying
								Value)
	Cash
	Cash	$	7,887,502	$	7,887,502	$	—	$	7,887,502
	Cash equivalents
	Money market funds		44,959,438		44,959,438		—		44,959,438
	Cash and cash equivalents	$	52,846,940	$	52,846,940	$	—	$	52,846,940
	Short-term investments (due within 1 year)
	U.S. government treasury obligations	$	5,009,194	$	5,013,850	$	—	$	5,013,850
	U.S. government agency obligations		33,598,370		33,609,886		—		33,609,886
	Corporate obligations		31,789,117		—		31,810,412		31,810,412
	Total short-term investments	$	70,396,681	$	38,623,736	$	31,810,412	$	70,434,148
	Long-term investments (due after 1 year
	through 2 years)
	U.S. government agency obligations	$	14,807,642	$	14,821,065	$	—	$	14,821,065
	Corporate obligations		10,743,707		—		10,750,594		10,750,594
	Total long-term investments	$	25,551,349	$	14,821,065	$	10,750,594	$	25,571,659

Property_and_Equipment_Tables

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2013
Property, Plant and Equipment [Abstract]	'
Property, Plant and Equipment [Table Text Block]	'
	Property and equipment consisted of the following:
				December 31,
		Estimated Useful Lives		2012		2013
	Laboratory equipment		7	$	3,748,201	$	4,796,393
	Office equipment and software		3 – 7		809,146		972,789
	Leasehold improvements		7		216,917		348,901
	Assets not in service				526,495		503,208
					5,300,759		6,621,291
	Less accumulated depreciation				-2,133,854		-2,781,865
				$	3,166,905	$	3,839,426

Leases_Tables

Leases (Tables)	12 Months Ended
	Dec. 31, 2013
Leases [Abstract]	'
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	'
	Future minimum lease payments for noncancellable operating leases as of December 31, 2013, are as follows:
	2014	$	825,810
	2015		143,524
	2016		154,663
	2017		158,474
	2018		26,677
	Thereafter		—
	Total minimum lease payments	$	1,309,148

Stockholders_Equity_Deficit_Ta

Stockholders' Equity (Deficit) (Tables)	12 Months Ended
	Dec. 31, 2013
Equity [Abstract]	'
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	'
	The weighted-average value of the individual options granted during 2011, 2012 and 2013 were determined using the following assumptions:
		Year Ended December 31,
		2011				2012			2013
	Weighted-average volatility			82.77	%		89.13	%			101	%
	Risk-free interest rate			2.27	%		1.1	%			1.31	%
	Weighted-average expected life (in years)			6.2			6.2				6.6
	Dividend yield			0	%		0	%			0	%
Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]	'
	The Company’s stock option activity and related information are summarized as follows:
			Options		Weighted-Average			Weighted-Average Remaining		Aggregate
					Exercise Price			Contractual Term (In Years)		Intrinsic
										Value
	Outstanding at		2,019,333		$	2.82
	January 1, 2011
	Granted during year		926,956			9.39
	Exercised during year		-283,061			2.1
	Expired during year		-23,039			7.64
	Forfeited during year		-48,180			7.07
	Outstanding at		2,592,009		$	5.12		7.38		$	1,652,483
	December 31, 2011
	Exercisable at		1,339,341			2.69		5.97			1,523,957
	December 31, 2011
	Outstanding at		2,592,009		$	5.12
	January 1, 2012
	Granted during year		1,492,395			4.61
	Exercised during year		-134,534			2.91
	Expired during year		-13,502			9.86
	Forfeited during year		-57,129			6.68
	Outstanding at		3,879,239		$	4.96		7.5		$	16,198,044
	December 31, 2012
	Exercisable at		1,676,016			3.83		5.72			8,882,339
	December 31, 2012
	Outstanding at		3,879,239			4.96
	January 1, 2013
	Granted during year		1,566,062			10.79
	Exercised during year		-188,699			3.42
	Expired during year		—
	Forfeited during year		-10,137			6.04
	Outstanding at		5,246,465		$	6.76		7.39		$	22,002,357
	December 31, 2013
	Exercisable at		2,269,438			4.59		5.73			13,968,005
	December 31, 2013
Schedule Of Share Based Compensation Non Vested Stock Options Activity [Table Text Block]	'
	The following is a rollforward of the Company’s nonvested stock options from January 1, 2011 to December 31, 2013.
			Options		Weighted-Average Grant Date Value
	Nonvested stock options at January 1, 2011		748,107		$	1.97
	Granted during year		926,956			6.83
	Vested during year		-330,132			1.97
	Expired during year		-44,083			5.22
	Forfeited during year		-48,180			4.81
	Nonvested at December 31, 2011		1,252,668		$	5.34
	Nonvested stock options at January 1, 2012		1,252,668		$	5.34
	Granted during year		1,492,395			3.42
	Vested during year		-484,711			4.51
	Expired during year		—			—
	Forfeited during year		-57,129			4.61
	Nonvested at December 31, 2012		2,203,223		$	4.24
	Nonvested stock options at January 1, 2013		2,203,223		$	4.24
	Granted during year		1,566,062			8.76
	Vested during year		-782,121			4.22
	Expired during year		—			—
	Forfeited during year		-10,137			4.58
	Nonvested at December 31, 2013		2,977,027		$	6.62

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	'
	A reconciliation of the expected income tax benefit (expense) computed using the federal statutory income tax rate to the Company’s effective income tax rate is as follows for years ended December 31, 2011, 2012, and 2013:
		December 31,
		2011		2012		2013
	Income tax computed at federal statutory tax rate	34	%	34	%	34	%
	State taxes, net of federal benefit	0.3	%	3.9	%	4.2	%
	International operations	-0.1	%	-0.2	%	-2.1	%
	Research and development credits	4	%	2.4	%	13.8	%
	Orphan drug credits	0	%	0	%	8.3	%
	Permanent differences	0.2	%	-2.2	%	-5.4	%
	Other	0	%	-0.2	%	-0.1	%
	Change in valuation allowance	-38.4	%	-37.7	%	-52.7	%
	Total	0	%	0	%	0	%
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	'
	Net deferred tax assets and liabilities are comprised of the following:
		December 31,
		2012			2013
	Deferred tax assets
	Net operating loss carryforwards	$	53,754,000		$	65,678,000
	Research and development credit carryforwards		7,110,000			9,592,000
	Orphan Drug Credit		—			1,495,000
	Stock Options		1,045,000			2,377,000
	Deferred revenue		5,355,000			—
	Other		91,000			120,000
	Deferred tax assets		67,355,000			79,262,000
	Deferred tax liabilities
	Deferred Revenue		—			-2,594,000
	Property and equipment		-143,000			-241,000
	Deferred tax liabilities	$	-143,000		$	-2,835,000
	Net deferred tax asset before valuation allowance	$	67,212,000		$	76,427,000
	Less valuation allowance		-67,212,000			-76,427,000
	Net deferred tax assets	$	—		$	—

Selected_Quarterly_Financial_D1

Selected Quarterly Financial Data (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]	'
Condensed Income Statement [Table Text Block]	'
	The following table summarizes the unaudited statements of operations for each quarter of 2013 and 2012 (in thousands except share and per share amounts):
			Quarters Ended
			March 31		June 30		September 30		December 31
	2013
	Revenue		$	14,514	$	16,483	$	16,600	$	17,274
	Operating Expenses:
	Research and development			12,259		18,607		13,501		13,533
	General and administrative			6,256		6,211		6,143		6,704
	Loss from operations			-4,001		-8,335		-3,044		-2,963
	Interest, net			139		126		111		89
	Other			—		-18		-108		-28
	Net loss		$	-3,862	$	-8,227	$	-3,041	$	-2,902
	Basic and diluted net loss per share(1)		$	-0.11	$	-0.23	$	-0.08	$	-0.08
	Weighted average common shares			35,930,265		35,991,402		36,077,440		36,146,061
	outstanding – basic and diluted(2)
			Quarters Ended
			March 31		June 30		September 30		December 31
	2012
	Revenue		$	—	$	7,813	$	12,415	$	14,454
	Operating Expenses:
	Research and development			6,417		8,806		9,930		10,518
	General and administrative			3,094		3,195		3,815		4,950
	Loss from operations			-9,511		-4,188		-1,330		-1,014
	Interest, net			-334		-252		95		190
	Other			75		-994		-4		-25
	Net loss		$	-9,770	$	-5,434	$	-1,239	$	-849
	Basic and diluted net loss per share(1)		$	-0.27	$	-0.15	$	-0.03	$	-0.02
	Weighted average common shares			35,798,530		35,843,312		35,881,112		35,910,490
	outstanding – basic and diluted(2)
		-1	Per common share amounts for the quarters and full years have been calculated separately. Accordingly, the sum of quarterly amounts may not equal the annual amount because of differences in the weighted average common shares outstanding during each period, principally due to the effect of share issuances by the Company during the year.
		-2	Diluted weighted average common shares outstanding are identical to basic weighted average common shares outstanding and diluted net loss per share is identical to basic net loss per share for all quarters of 2013 and 2012 because common share equivalents are excluded from the calculations of diluted weighted average common shares outstanding for those quarters, as their effect is anti-dilutive.

Nature_of_Business_and_Organiz1

Nature of Business and Organization (Details Textual) (USD $)	0 Months Ended
In Millions, except Share data, unless otherwise specified	Aug. 02, 2011	Feb. 09, 2011
Nature of Business and Organization [Line Items]	'	'
Stock Issued During Period, Shares, New Issues	4,968,321	14,375,000
Proceeds from Issuance of Common Stock	$66.70	$78.20
Stock Issued During Period Shares Conversion Of Subordinated Notes To Common Stock	'	2,335,823
Common Stock, Conversion Basis	'	'conversion price of $5.10 per share(85% of the original issue price of the shares sold in the initial public offering)
Over Allotment Option by Underwriters [Member]	'	'
Nature of Business and Organization [Line Items]	'	'
Stock Issued During Period, Shares, New Issues	871,489	1,875,000

Significant_Accounting_Policie2

Significant Accounting Policies (Details Textual) (USD $)	0 Months Ended
In Millions, unless otherwise specified	Jan. 10, 2011	Dec. 31, 2013
		Research and Development Arrangement [Member]
Significant Accounting Policies [Line Items]	'	'
Stockholders Equity, Reverse Stock Split	'Company effected a 1.00 for 1.91 reverse stock split	'
Prepaid Expense and Other Assets, Noncurrent	'	$2.30

Net_Loss_Per_Share_Details

Net Loss Per Share (Details) (USD $)

3 Months Ended

12 Months Ended

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Numerator:

'

'

'

'

'

'

'

'

'

'

'

Net loss

($2,902)

($3,041)

($8,227)

($3,862)

($849)

($1,239)

($5,434)

($9,770)

($18,032,438)

($17,291,758)

($40,531,613)

Denominator:

'

'

'

'

'

'

'

'

'

'

'

Weighted-average common shares outstanding (in shares)

36,146,061

[1]

36,077,440

[1]

35,991,402

[1]

35,930,265

[1]

35,910,490

[1]

35,881,112

[1]

35,843,312

[1]

35,798,530

[1]

36,036,996

35,858,757

29,003,991

Basic and diluted net loss per share (in dollars per share)

($0.08)

[2]

($0.08)

[2]

($0.23)

[2]

($0.11)

[2]

($0.02)

[2]

($0.03)

[2]

($0.15)

[2]

($0.27)

[2]

($0.50)

($0.48)

($1.40)

[1]

Diluted weighted average common shares outstanding are identical to basic weighted average common shares outstanding and diluted net loss per share is identical to basic net loss per share for all quarters of 2013 and 2012 because common share equivalents are excluded from the calculations of diluted weighted average common shares outstanding for those quarters, as their effect is anti-dilutive.

[2]

Per common share amounts for the quarters and full years have been calculated separately. Accordingly, the sum of quarterly amounts may not equal the annual amount because of differences in the weighted average common shares outstanding during each period, principally due to the effect of share issuances by the Company during the year.

Net_Loss_Per_Share_Details_1

Net Loss Per Share (Details 1)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'
Potential Common Stock Equivalents, Outstanding	5,551,761	4,287,195	2,997,190
Outstanding Common Stock Options [Member]	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'
Potential Common Stock Equivalents, Outstanding	5,246,465	3,879,239	2,592,009
Outstanding RSUs [Member]	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'
Potential Common Stock Equivalents, Outstanding	270,649	273,988	271,213
Outstanding warrants [Member]	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'
Potential Common Stock Equivalents, Outstanding	34,647	133,968	133,968

Other_Comprehensive_Income_Los2

Other Comprehensive Income (Loss) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Other Comprehensive Income Loss [Line Items]	'	'	'
Foreign Currency Translation Gains (Losses), Beginning balance	($5,011)	($5,718)	$0
Foreign Currency Translation Gains (Losses), Unrealized gain (loss)	-6,805	707	-5,718
Foreign Currency Translation Gains (Losses), Net amount reclassified to net loss	0	0	0
Foreign Currency Translation Gains (Losses), Other comprehensive income (loss)	-6,805	707	-5,718
Foreign Currency Translation Gains (Losses), Ending balance	-11,816	-5,011	-5,718
Unrealized Net Gains (Losses) on Securities, Beginning balance	77,760	-546	0
Unrealized Net Gains (Losses) on Securities, Unrealized gain (loss)	-4,203	78,204	-546
Unrealized Net Gains (Losses) on Securities, Net amount reclassified to net loss	-5,050	102	0
Unrealized Net Gains (Losses) on Securities, Other comprehensive income (loss)	-9,253	78,306	-546
Unrealized Net Gains (Losses) on Securities, Ending balance	68,507	77,760	-546
Accumulated Other Comprehensive Gains (Losses), Beginning balance	72,749	-6,264	0
Accumulated Other Comprehensive Gains (Losses), Unrealized gain (loss)	-11,008	78,911	-6,264
Accumulated Other Comprehensive Gains (Losses), Net amount reclassified to net loss	-5,050	102	0
Accumulated Other Comprehensive Gains (Losses), Other comprehensive income (loss)	-16,058	79,013	-6,264
Accumulated Other Comprehensive Gains (Losses), Ending balance	$56,691	$72,749	($6,264)

Other_Comprehensive_Income_Los3

Other Comprehensive Income (Loss) (Details 1) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Other Comprehensive Income Loss [Line Items]	'	'	'
Amount Reclassified from Accumulated Other Comprehensive Loss, Unrealized Net Gains (Losses) on Securities	$5,050	($102)	$0
Other Income (Expense) [Member]	'	'	'
Other Comprehensive Income Loss [Line Items]	'	'	'
Amount Reclassified from Accumulated Other Comprehensive Loss, Unrealized Net Gains (Losses) on Securities	$5,050	'	'

Investments_Details

Investments (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash	'	'	'	'
Cash	$7,887,502	$5,227,208	'	'
Cash equivalents	'	'	'	'
Money market funds	44,959,438	28,769,658	'	'
Cash and cash equivalents	52,846,940	33,996,866	61,352,483	16,872,783
Short-term investments (due within 1 year)	'	'	'	'
Total short-term investments	70,434,148	141,840,823	'	'
Long-term investments (due after 1 year through 2 years)	'	'	'	'
Total long-term investments	25,571,659	25,540,649	'	'
US Treasury Securities [Member]	'	'	'	'
Short-term investments (due within 1 year)	'	'	'	'
Total short-term investments	5,013,850	10,053,393	'	'
Long-term investments (due after 1 year through 2 years)	'	'	'	'
Total long-term investments	'	5,030,699	'	'
US Government Agencies Debt Securities [Member]	'	'	'	'
Short-term investments (due within 1 year)	'	'	'	'
Total short-term investments	33,609,886	89,847,365	'	'
Long-term investments (due after 1 year through 2 years)	'	'	'	'
Total long-term investments	14,821,065	17,463,067	'	'
Corporate Debt Securities [Member]	'	'	'	'
Short-term investments (due within 1 year)	'	'	'	'
Total short-term investments	31,810,412	41,940,065	'	'
Long-term investments (due after 1 year through 2 years)	'	'	'	'
Total long-term investments	10,750,594	3,046,883	'	'
Fair Value, Inputs, Level 1 [Member]	'	'	'	'
Cash	'	'	'	'
Cash	7,887,502	5,227,208	'	'
Cash equivalents	'	'	'	'
Money market funds	44,959,438	28,769,658	'	'
Cash and cash equivalents	52,846,940	33,996,866	'	'
Short-term investments (due within 1 year)	'	'	'	'
Total short-term investments	38,623,736	99,900,758	'	'
Long-term investments (due after 1 year through 2 years)	'	'	'	'
Total long-term investments	14,821,065	22,493,766	'	'
Fair Value, Inputs, Level 1 [Member] | US Treasury Securities [Member]	'	'	'	'
Short-term investments (due within 1 year)	'	'	'	'
Total short-term investments	5,013,850	10,053,393	'	'
Long-term investments (due after 1 year through 2 years)	'	'	'	'
Total long-term investments	'	5,030,699	'	'
Fair Value, Inputs, Level 1 [Member] | US Government Agencies Debt Securities [Member]	'	'	'	'
Short-term investments (due within 1 year)	'	'	'	'
Total short-term investments	33,609,886	89,847,365	'	'
Long-term investments (due after 1 year through 2 years)	'	'	'	'
Total long-term investments	14,821,065	17,463,067	'	'
Fair Value, Inputs, Level 1 [Member] | Corporate Debt Securities [Member]	'	'	'	'
Short-term investments (due within 1 year)	'	'	'	'
Total short-term investments	0	0	'	'
Long-term investments (due after 1 year through 2 years)	'	'	'	'
Total long-term investments	0	0	'	'
Fair Value, Inputs, Level 2 [Member]	'	'	'	'
Cash	'	'	'	'
Cash	0	0	'	'
Cash equivalents	'	'	'	'
Money market funds	0	0	'	'
Cash and cash equivalents	0	0	'	'
Short-term investments (due within 1 year)	'	'	'	'
Total short-term investments	31,810,412	41,940,065	'	'
Long-term investments (due after 1 year through 2 years)	'	'	'	'
Total long-term investments	10,750,594	3,046,883	'	'
Fair Value, Inputs, Level 2 [Member] | US Treasury Securities [Member]	'	'	'	'
Short-term investments (due within 1 year)	'	'	'	'
Total short-term investments	0	0	'	'
Long-term investments (due after 1 year through 2 years)	'	'	'	'
Total long-term investments	'	0	'	'
Fair Value, Inputs, Level 2 [Member] | US Government Agencies Debt Securities [Member]	'	'	'	'
Short-term investments (due within 1 year)	'	'	'	'
Total short-term investments	0	0	'	'
Long-term investments (due after 1 year through 2 years)	'	'	'	'
Total long-term investments	0	0	'	'
Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member]	'	'	'	'
Short-term investments (due within 1 year)	'	'	'	'
Total short-term investments	31,810,412	41,940,065	'	'
Long-term investments (due after 1 year through 2 years)	'	'	'	'
Total long-term investments	10,750,594	3,046,883	'	'
Cost [Member]	'	'	'	'
Cash	'	'	'	'
Cash	7,887,502	5,227,208	'	'
Cash equivalents	'	'	'	'
Money market funds	44,959,438	28,769,658	'	'
Cash and cash equivalents	52,846,940	33,996,866	'	'
Short-term investments (due within 1 year)	'	'	'	'
Total short-term investments	70,396,681	141,779,548	'	'
Long-term investments (due after 1 year through 2 years)	'	'	'	'
Total long-term investments	25,551,349	25,524,163	'	'
Cost [Member] | US Treasury Securities [Member]	'	'	'	'
Short-term investments (due within 1 year)	'	'	'	'
Total short-term investments	5,009,194	10,049,323	'	'
Long-term investments (due after 1 year through 2 years)	'	'	'	'
Total long-term investments	'	5,024,697	'	'
Cost [Member] | US Government Agencies Debt Securities [Member]	'	'	'	'
Short-term investments (due within 1 year)	'	'	'	'
Total short-term investments	33,598,370	89,824,358	'	'
Long-term investments (due after 1 year through 2 years)	'	'	'	'
Total long-term investments	14,807,642	17,455,606	'	'
Cost [Member] | Corporate Debt Securities [Member]	'	'	'	'
Short-term investments (due within 1 year)	'	'	'	'
Total short-term investments	31,789,117	41,905,867	'	'
Long-term investments (due after 1 year through 2 years)	'	'	'	'
Total long-term investments	$10,743,707	$3,043,860	'	'

Investments_Details_Textual

Investments (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Schedule of Trading Securities and Other Trading Assets [Line Items]	'	'
Unrealized Gain on Securities	$76,630	$79,031
Unrealized Loss on Securities	$8,122	$1,271

Property_and_Equipment_Details

Property and Equipment (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]	'	'
Property, Plant and Equipment, Gross	$6,621,291	$5,300,759
Less accumulated depreciation	-2,781,865	-2,133,854
Property, Plant and Equipment, Net, Total	3,839,426	3,166,905
Laboratory equipment [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, Plant and Equipment, Gross	4,796,393	3,748,201
Property, Plant and Equipment, Useful Life	'7 years	'
Office Equipment and software [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, Plant and Equipment, Gross	972,789	809,146
Office Equipment and software [Member] | Maximum [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, Plant and Equipment, Useful Life	'7 years	'
Office Equipment and software [Member] | Minimum [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, Plant and Equipment, Useful Life	'3 years	'
Leasehold Improvements [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, Plant and Equipment, Gross	348,901	216,917
Property, Plant and Equipment, Useful Life	'7 years	'
Assets not in service [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, Plant and Equipment, Gross	$503,208	$526,495

Property_and_Equipment_Details1

Property and Equipment (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Property, Plant and Equipment [Line Items]	'	'	'
Depreciation, Total	$674,725	$358,367	$262,518

LongTerm_Debt_Details_Textual

Long-Term Debt (Details Textual) (USD $)	12 Months Ended			1 Months Ended		12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Jun. 30, 2012	Aug. 31, 2010	Dec. 31, 2010
				Mid Cap Financial and Silicon Valley Bank [Member]	Mid Cap Financial and Silicon Valley Bank [Member]	Mid Cap Financial and Silicon Valley Bank [Member]
Debt Instrument [Line Items]	'	'	'	'	'	'
Debt Instrument, Face Amount	'	'	'	'	$15,000,000	'
Proceeds from Bank Debt	'	'	'	'	10,000,000	5,000,000
Gains (Losses) on Extinguishment of Debt	0	-992,281	0	-992,000	'	'
Prepayment Penalty Rate	'	'	'	5.00%	'	'
Prepayment Penalty Amount	'	'	'	615,000	'	'
Debtor Reorganization Items, Write-off of Deferred Financing Costs and Debt Discounts	'	'	'	377,000	'	'
Preferred Stock Warrants Issued To Acquire Number Of Convertible Preferred	'	'	'	'	'	64,674
Fair Value Of Preferred Stock Warrants	'	'	'	'	'	219,322
Interest paid	$0	$655,834	$1,334,507	'	'	'

Warrants_Details_Textual

Warrants (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2010	Dec. 31, 2013	Dec. 31, 2007
		GECC and Oxford [Member]	GECC and Oxford [Member]
Class of Stock [Line Items]	'	'	'
Warrants Issued To Acquire Number Of Convertible Preferred Stock Shares	'	'	69,294
Warrants Exercise Price	$8.12	'	'
Stock Issued During Period Shares Warrants Exercised	'	47,791	'

Leases_Details

Leases (Details) (USD $)	Dec. 31, 2013
Operating Leased Assets [Line Items]	'
2014	$825,810
2015	143,524
2016	154,663
2017	158,474
2018	26,677
Thereafter	0
Total minimum lease payments	$1,309,148

Leases_Details_Textual

Leases (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating Leased Assets [Line Items]	'	'	'
Operating Leases, Rent Expense, Net, Total	$784,531	$512,855	$421,297

Stockholders_Equity_Deficit_De

Stockholders' Equity (Deficit) (Details)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Stockholdersb Equity Deficit [Line Items]	'	'	'
Weighted-average volatility	101.00%	89.13%	82.77%
Risk-free interest rate	1.31%	1.10%	2.27%
Weighted-average expected life (in years)	'6 years 7 months 6 days	'6 years 2 months 12 days	'6 years 2 months 12 days
Dividend yield	0.00%	0.00%	0.00%

Stockholders_Equity_Deficit_De1

Stockholders' Equity (Deficit) (Details 1) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Stockholdersb Equity Deficit [Line Items]	'	'	'
Options, Outstanding, Beginning Balance	3,879,239	2,592,009	2,019,333
Options, Granted during year	1,566,062	1,492,395	926,956
Options, Exercised during year	-188,699	-134,534	-283,061
Options, Expired during year	0	-13,502	-23,039
Options, Forfeited during year	-10,137	-57,129	-48,180
Options, Outstanding, Ending Balance	5,246,465	3,879,239	2,592,009
Exercisable	2,269,438	1,676,016	1,339,341
Weighted Average Exercise Price, Outstanding, Beginning Balance	$4.96	$5.12	$2.82
Weighted Average Exercise Price, Granted during year	$10.79	$4.61	$9.39
Weighted Average Exercise Price, Exercised during year	$3.42	$2.91	$2.10
Weighted average Exercise Price, Expired during year	'	$9.86	$7.64
Weighted Average Exercise Price, Forfeited during year	$6.04	$6.68	$7.07
Weighted Average Exercise Price, Outstanding Ending Balance	$6.76	$4.96	$5.12
Weighted Average Exercise Price, Exercisable	$4.59	$3.83	$2.69
Weighted Average Remaining Contractual Term, Outstanding, Ending Balance	'7 years 4 months 20 days	'7 years 6 months	'7 years 4 months 17 days
Weighted Average Remaining Contractual Term, Exercisable	'5 years 8 months 23 days	'5 years 8 months 19 days	'5 years 11 months 19 days
Aggregate Intrinsic Value, Outstanding, Ending Balance	$22,002,357	$16,198,044	$1,652,483
Aggregate Intrinsic Value, Exercisable	$13,968,005	$8,882,339	$1,523,957

Stockholders_Equity_Deficit_De2

Stockholders' Equity (Deficit) (Details 2) (Non Vested Stock Options [Member], USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Non Vested Stock Options [Member]	'	'	'
Stockholdersb Equity Deficit [Line Items]	'	'	'
Nonvested stock options, Beginning Balance	2,203,223	1,252,668	748,107
Options, Granted during year	1,566,062	1,492,395	926,956
Options, Vested during year	-782,121	-484,711	-330,132
Options, Expired during year	0	0	-44,083
Options, Forfeited during year	-10,137	-57,129	-48,180
Nonvested stock options, Ending Balance	2,977,027	2,203,223	1,252,668
Weighted-Average Grant Date Value, Nonvested stock options, Beginning Balance	$4.24	$5.34	$1.97
Weighted-Average Grant Date Value, Granted during year	$8.76	$3.42	$6.83
Weighted-Average Grant Date Value, Vested during year	$4.22	$4.51	$1.97
Weighted-Average Grant Date Value, Expired during year	$0	$0	$5.22
Weighted-Average Grant Date Value, Forfeited during year	$4.58	$4.61	$4.81
Weighted-Average Grant Date Value, Nonvested stock options, Ending Balance	$6.62	$4.24	$5.34

Stockholders_Equity_Deficit_De3

Stockholders' Equity (Deficit) (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Stockholdersb Equity Deficit [Line Items]	'	'	'	'
Common Stock, Shares Authorized	100,000,000	100,000,000	'	'
Share Based Compensation Arrangement By Share Based Payment Option Granted	$13,725,956	$5,098,734	'	'
Share-based Compensation	6,059,005	3,022,693	1,960,345	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value	3,303,701	2,216,038	650,068	'
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options	13,900,183	6,719,346	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value	1,884,651	511,790	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	5,246,465	3,879,239	2,592,009	2,019,333
Restricted Stock Units (RSUs) [Member]	'	'	'	'
Stockholdersb Equity Deficit [Line Items]	'	'	'	'
Percentage of Historical Forfeiture	6.49%	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	270,649	'	'	'
Share Based Compensation Arrangement By Share Based Payment Award Vesting Term Description	'PRSUs will vest fifty percent based on the performance condition of commercial approval and fifty percent one year thereafter	'	'	'
Employee Benefits and Share-based Compensation	$2,700,000	'	'	'
Equity Incentive Plan 2010 [Member]	'	'	'	'
Stockholdersb Equity Deficit [Line Items]	'	'	'	'
Common Stock, Shares Authorized	6,625,563	5,195,563	'	'

Income_Taxes_Details

Income Taxes (Details)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax [Line Items]	'	'	'
Income tax computed at federal statutory tax rate	34.00%	34.00%	34.00%
State taxes, net of federal benefit	4.20%	3.90%	0.30%
International operations	-2.10%	-0.20%	-0.10%
Research and development credits	13.80%	2.40%	4.00%
Orphan drug credits	8.30%	0.00%	0.00%
Permanent differences	-5.40%	-2.20%	0.20%
Other	-0.10%	-0.20%	0.00%
Change in valuation allowance	-52.70%	-37.70%	-38.40%
Total	0.00%	0.00%	0.00%

Income_Taxes_Details_1

Income Taxes (Details 1) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Deferred tax assets	'	'
Net operating loss carryforwards	$65,678,000	$53,754,000
Research and development credit carryforwards	9,592,000	7,110,000
Orphan Drug Credit	1,495,000	0
Stock Options	2,377,000	1,045,000
Deferred revenue	0	5,355,000
Other	120,000	91,000
Deferred tax assets	79,262,000	67,355,000
Deferred tax liabilities	'	'
Deferred Revenue	-2,594,000	0
Property and equipment	-241,000	-143,000
Deferred tax liabilities	-2,385,000	-143,000
Net deferred tax asset before valuation allowance	76,427,000	67,212,000
Less valuation allowance	-76,427,000	-67,212,000
Net deferred tax assets	$0	$0

Income_Taxes_Details_Textual

Income Taxes (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2013
Income Taxes [Line Items]	'
Net Operating Loss Carryforwards Federal	$163,200,000
Net Operating Loss Carryforwards State	214,700,000
Operating Loss Carryforwards, Expiration Dates	'2022
For 2013 [Member]	'
Income Taxes [Line Items]	'
Operating Loss Carryforwards	94,200,000
For 2014 and 2015 [Member]	'
Income Taxes [Line Items]	'
Operating Loss Carryforwards	39,000,000
For 2016 [Member]	'
Income Taxes [Line Items]	'
Operating Loss Carryforwards	29,700,000
For 2017 [Member]	'
Income Taxes [Line Items]	'
Operating Loss Carryforwards	$16,800,000

Collaborations_Details_Textual

Collaborations (Details Textual) (USD $)

1 Months Ended

3 Months Ended

12 Months Ended

1 Months Ended

1 Months Ended

12 Months Ended

1 Months Ended

Apr. 30, 2012

Oct. 31, 2007

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Feb. 28, 2011

Dec. 31, 2009

Dec. 31, 1995

Aug. 31, 2013

Dec. 31, 2013

Apr. 30, 2012

Apr. 30, 2012

Apr. 30, 2012

Dec. 31, 2012

Apr. 30, 2012

Apr. 30, 2012

NMP [Member]

NMP [Member]

Development Milestones [Member]

Sales Based Milestones [Member]

Non Substantive Milestone [Member]

Non Substantive Milestone [Member]

Maximum [Member]

Minimum [Member]

Development Milestones [Member]

Development Milestones [Member]

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Research and Development Expense

'

$300,000

$13,533

$13,501

$18,607

$12,259

$10,518

$9,930

$8,806

$6,417

$57,898,971

$35,670,418

$28,827,746

'

'

'

'

'

'

'

'

'

'

'

Maintenance Costs

'

50,000

'

'

'

'

'

'

'

'

100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Additional Contingent Payable Upon Satisfaction Of Certain Criteria

'

'

'

'

'

'

'

'

'

'

'

'

'

6,300,000

'

'

'

'

'

'

'

'

'

'

Annual Minimum Royalty Payable

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

12,500

'

'

'

'

'

'

'

'

Annual Payments Payable Until First Commercial Sale

'

'

'

'

'

'

'

'

'

'

'

'

'

'

15,000

'

'

'

'

'

'

'

'

'

Clinical And Regulatory Milestone Payments

'

'

'

'

'

'

'

'

'

'

'

'

'

'

500,000

'

'

'

'

'

'

'

'

'

Penalties Payable

'

'

'

'

'

'

'

'

'

'

'

'

'

'

300,000

'

'

'

'

'

'

'

'

'

Annual Milestone Payments

'

'

'

'

'

'

'

'

'

'

'

'

'

'

100,000

'

'

'

'

'

'

'

'

'

Future Milestone Payments

'

'

'

'

'

'

'

'

'

'

'

'

'

'

500,000

'

'

'

'

'

'

'

'

'

Payments to Acquire in Process Research and Development

120,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Non-refundable Upfront Payments Received

120,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,000,000

'

'

'

5,000,000

'

'

'

Collaboration Revenue

'

'

'

'

'

'

'

'

'

'

64,870,919

34,682,111

191,023

'

'

'

'

'

'

'

'

'

'

'

Deferred Revenue

'

'

59,700,000

'

'

'

104,000,000

'

'

'

59,700,000

104,000,000

'

'

'

'

'

900,000

'

'

'

'

'

'

Potential Milestone Payments

880,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

4,500,000

'

380,000,000

500,000,000

'

5,000,000

45,000,000

5,000,000

Maximum Eligible Amount for Milestone Payments

875,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

License Costs

'

'

'

'

'

'

'

'

'

'

51,500,000

27,500,000

'

'

'

'

'

'

'

'

'

'

'

'

License and Services Revenue

'

'

'

'

'

'

'

'

'

'

$13,400,000

$7,200,000

'

'

'

'

'

'

'

'

'

'

'

'

RelatedParty_Transactions_Deta

Related-Party Transactions (Details Textual) (USD $)

1 Months Ended

3 Months Ended

12 Months Ended

Oct. 31, 2007

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Related Party Transaction [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Research and Development Expense

$300,000

$13,533

$13,501

$18,607

$12,259

$10,518

$9,930

$8,806

$6,417

$57,898,971

$35,670,418

$28,827,746

Proceeds from License Fees Received

'

'

'

'

'

'

'

'

'

'

'

191,000

License and Maintenance Revenue

'

'

'

'

'

'

'

'

'

20,000

20,000

'

Chief Operating Officer [Member]

'

'

'

'

'

'

'

'

'

'

'

'

Related Party Transaction [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Research and Development Expense

'

'

'

'

'

'

'

'

'

824,559

788,737

517,500

Patents [Member]

'

'

'

'

'

'

'

'

'

'

'

'

Related Party Transaction [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Reimbursement Revenue

'

'

'

'

'

'

'

'

'

'

'

50,000

Research and Development Expense [Member]

'

'

'

'

'

'

'

'

'

'

'

'

Related Party Transaction [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Reimbursable Research And Development Expenses

'

'

'

'

'

'

'

'

'

$27,394

$54,475

'

Selected_Quarterly_Financial_D2

Selected Quarterly Financial Data (unaudited) (Details) (USD $)	1 Months Ended	3 Months Ended																12 Months Ended
	Oct. 31, 2007	Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2012		Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Selected Quarterly Financial Data unaudited [Line Items]	'	'		'		'		'		'		'		'		'		'	'	'
Revenue	'	$17,274		$16,600		$16,483		$14,514		$14,454		$12,415		$7,813		$0		$64,870,919	$34,682,111	$191,023
Operating Expenses:	'	'		'		'		'		'		'		'		'		'	'	'
Research and development	300,000	13,533		13,501		18,607		12,259		10,518		9,930		8,806		6,417		57,898,971	35,670,418	28,827,746
General and administrative	'	6,704		6,143		6,211		6,256		4,950		3,815		3,195		3,094		25,313,731	15,054,369	10,000,000
Loss from operations	'	-2,963		-3,044		-8,335		-4,001		-1,014		-1,330		-4,188		-9,511		-18,341,783	-16,042,676	-38,636,723
Interest, net	'	89		111		126		139		190		95		-252		-334		'	'	'
Other	'	-28		-108		-18		0		-25		-4		-994		75		-153,702	-947,834	-36,466
Net loss	'	($2,902)		($3,041)		($8,227)		($3,862)		($849)		($1,239)		($5,434)		($9,770)		($18,032,438)	($17,291,758)	($40,531,613)
Basic and diluted net loss per share (in dollars per share)	'	($0.08)	[1]	($0.08)	[1]	($0.23)	[1]	($0.11)	[1]	($0.02)	[1]	($0.03)	[1]	($0.15)	[1]	($0.27)	[1]	($0.50)	($0.48)	($1.40)
Weighted average common shares outstanding - basic and diluted (in shares)	'	36,146,061	[2]	36,077,440	[2]	35,991,402	[2]	35,930,265	[2]	35,910,490	[2]	35,881,112	[2]	35,843,312	[2]	35,798,530	[2]	36,036,996	35,858,757	29,003,991
[1]	Per common share amounts for the quarters and full years have been calculated separately. Accordingly, the sum of quarterly amounts may not equal the annual amount because of differences in the weighted average common shares outstanding during each period, principally due to the effect of share issuances by the Company during the year.
[2]	Diluted weighted average common shares outstanding are identical to basic weighted average common shares outstanding and diluted net loss per share is identical to basic net loss per share for all quarters of 2013 and 2012 because common share equivalents are excluded from the calculations of diluted weighted average common shares outstanding for those quarters, as their effect is anti-dilutive.